diff --git a/src/actor.h b/src/actor.h
index 3150bc1ac2..66b4163a1a 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -937,9 +937,6 @@ public:
 	TObjPtr<AInventory>	Inventory;		// [RH] This actor's inventory
 	DWORD			InventoryID;	// A unique ID to keep track of inventory items
 
-	//Added by MC:
-	SDWORD id;						// Player ID (for items, # in list.)
-
 	BYTE smokecounter;
 	BYTE FloatBobPhase;
 	BYTE FriendPlayer;				// [RH] Player # + 1 this friendly monster works for (so 0 is no player, 1 is player 0, etc)
diff --git a/src/b_func.cpp b/src/b_func.cpp
index d79e5df118..2703a19337 100644
--- a/src/b_func.cpp
+++ b/src/b_func.cpp
@@ -249,7 +249,7 @@ shootmissile:
 
 		if (m)
 		{
-			if (inc[actor->id])
+			if (inc[actor->player - players])
 				actor->player->angle += m;
 			else
 				actor->player->angle -= m;
@@ -257,7 +257,7 @@ shootmissile:
 
 		if (abs (actor->player->angle - actor->angle) < 4*ANGLE_1)
 		{
-			inc[actor->id] = !inc[actor->id];
+			inc[actor->player - players] = !inc[actor->player - players];
 		}
 
 		if (Check_LOS (actor, enemy, (SHOOTFOV/2)))
diff --git a/src/b_move.cpp b/src/b_move.cpp
index b456c0c84e..0345bccfb4 100644
--- a/src/b_move.cpp
+++ b/src/b_move.cpp
@@ -17,20 +17,7 @@
 #include "gi.h"
 #include "a_keys.h"
 #include "d_event.h"
-
-enum dirtype_t
-{
-    DI_EAST,
-    DI_NORTHEAST,
-    DI_NORTH,
-    DI_NORTHWEST,
-    DI_WEST,
-    DI_SOUTHWEST,
-    DI_SOUTH,
-    DI_SOUTHEAST,
-    DI_NODIR,
-    NUMDIRS
-};
+#include "p_enemy.h"
 
 static FRandom pr_botopendoor ("BotOpenDoor");
 static FRandom pr_bottrywalk ("BotTryWalk");
@@ -39,10 +26,6 @@ static FRandom pr_botnewchasedir ("BotNewChaseDir");
 // borrow some tables from p_enemy.cpp
 extern dirtype_t opposite[9];
 extern dirtype_t diags[4];
-extern fixed_t xspeed[8];
-extern fixed_t yspeed[8];
-
-extern TArray<line_t *> spechit;
 
 //Called while the bot moves after its player->dest mobj
 //which can be a weapon/enemy/item whatever.
diff --git a/src/ct_chat.cpp b/src/ct_chat.cpp
index c0c1f13f0a..697d72c583 100644
--- a/src/ct_chat.cpp
+++ b/src/ct_chat.cpp
@@ -273,7 +273,8 @@ void CT_Drawer (void)
 
 	if (players[consoleplayer].camera != NULL &&
 		(Button_ShowScores.bDown ||
-		 players[consoleplayer].camera->health <= 0) &&
+		 players[consoleplayer].camera->health <= 0 ||
+		 SB_ForceActive) &&
 		 // Don't draw during intermission, since it has its own scoreboard in wi_stuff.cpp.
 		 gamestate != GS_INTERMISSION)
 	{
diff --git a/src/d_net.cpp b/src/d_net.cpp
index d33f47e38a..bc4bc73523 100644
--- a/src/d_net.cpp
+++ b/src/d_net.cpp
@@ -39,7 +39,6 @@
 #include "cmdlib.h"
 #include "s_sound.h"
 #include "m_cheat.h"
-#include "p_effect.h"
 #include "p_local.h"
 #include "c_dispatch.h"
 #include "sbar.h"
@@ -670,6 +669,9 @@ void PlayerIsGone (int netnode, int netconsole)
 {
 	int i;
 
+	if (!nodeingame[netnode])
+		return;
+
 	for (i = netnode + 1; i < doomcom.numnodes; ++i)
 	{
 		if (nodeingame[i])
@@ -680,77 +682,40 @@ void PlayerIsGone (int netnode, int netconsole)
 		doomcom.numnodes = netnode;
 	}
 
+	if (playeringame[netconsole])
+	{
+		players[netconsole].playerstate = PST_GONE;
+	}
 	nodeingame[netnode] = false;
-	playeringame[netconsole] = false;
 	nodejustleft[netnode] = false;
 
-	if (deathmatch)
-	{
-		Printf ("%s left the game with %d frags\n",
-			players[netconsole].userinfo.GetName(),
-			players[netconsole].fragcount);
-	}
-	else
-	{
-		Printf ("%s left the game\n", players[netconsole].userinfo.GetName());
-	}
-
-	// [RH] Revert each player to their own view if spying through the player who left
-	for (int ii = 0; ii < MAXPLAYERS; ++ii)
-	{
-		if (playeringame[ii] && players[ii].camera == players[netconsole].mo)
-		{
-			players[ii].camera = players[ii].mo;
-			if (ii == consoleplayer && StatusBar != NULL)
-			{
-				StatusBar->AttachToPlayer (&players[ii]);
-			}
-		}
-	}
-
-	// [RH] Make the player disappear
-	FBehavior::StaticStopMyScripts (players[netconsole].mo);
-	if (players[netconsole].mo != NULL)
-	{
-		P_DisconnectEffect (players[netconsole].mo);
-		players[netconsole].mo->player = NULL;
-		players[netconsole].mo->Destroy ();
-		if (!(players[netconsole].mo->ObjectFlags & OF_EuthanizeMe))
-		{ // We just destroyed a morphed player, so now the original player
-		  // has taken their place. Destroy that one too.
-			players[netconsole].mo->Destroy();
-		}
-		players[netconsole].mo = NULL;
-		players[netconsole].camera = NULL;
-	}
-	// [RH] Let the scripts know the player left
-	FBehavior::StaticStartTypedScripts (SCRIPT_Disconnect, NULL, true, netconsole);
 	if (netconsole == Net_Arbitrator)
 	{
-		bglobal.RemoveAllBots (true);
-		Printf ("Removed all bots\n");
+		bglobal.RemoveAllBots(true);
+		Printf("Removed all bots\n");
 
 		// Pick a new network arbitrator
 		for (int i = 0; i < MAXPLAYERS; i++)
 		{
-			if (playeringame[i] && !players[i].isbot)
+			if (i != netconsole && playeringame[i] && !players[i].isbot)
 			{
 				Net_Arbitrator = i;
 				players[i].settings_controller = true;
-				Printf ("%s is the new arbitrator\n", players[i].userinfo.GetName());
+				Printf("%s is the new arbitrator\n", players[i].userinfo.GetName());
 				break;
 			}
 		}
-		if (debugfile && NetMode == NET_PacketServer)
+	}
+
+	if (debugfile && NetMode == NET_PacketServer)
+	{
+		if (Net_Arbitrator == consoleplayer)
 		{
-			if (Net_Arbitrator == consoleplayer)
-			{
-				fprintf (debugfile, "I am the new master!\n");
-			}
-			else
-			{
-				fprintf (debugfile, "Node %d is the new master!\n", nodeforplayer[Net_Arbitrator]);
-			}
+			fprintf(debugfile, "I am the new master!\n");
+		}
+		else
+		{
+			fprintf(debugfile, "Node %d is the new master!\n", nodeforplayer[Net_Arbitrator]);
 		}
 	}
 
@@ -1760,10 +1725,19 @@ void D_CheckNetGame (void)
 		resendto[i] = 0;				// which tic to start sending
 	}
 
+	// Packet server has proven to be rather slow over the internet. Print a warning about it.
+	v = Args->CheckValue("-netmode");
+	if (v != NULL && (atoi(v) != 0))
+	{
+		Printf(TEXTCOLOR_YELLOW "Notice: Using PacketServer (netmode 1) over the internet is prone to running too slow on some internet configurations."
+			"\nIf the game is running well below excpected speeds, use netmode 0 (P2P) instead.\n");
+	}
+
 	// I_InitNetwork sets doomcom and netgame
 	if (I_InitNetwork ())
 	{
-		NetMode = NET_PacketServer;
+		// For now, stop auto selecting PacketServer, as it's more likely to cause confusion.
+		//NetMode = NET_PacketServer;
 	}
 	if (doomcom.id != DOOMCOM_ID)
 	{
diff --git a/src/d_netinfo.cpp b/src/d_netinfo.cpp
index f3f83e25e5..6c5fbb6c5c 100644
--- a/src/d_netinfo.cpp
+++ b/src/d_netinfo.cpp
@@ -60,9 +60,6 @@
 
 static FRandom pr_pickteam ("PickRandomTeam");
 
-extern bool st_firsttime;
-EXTERN_CVAR (Bool, teamplay)
-
 CVAR (Float,	autoaim,				5000.f,		CVAR_USERINFO | CVAR_ARCHIVE);
 CVAR (String,	name,					"Player",	CVAR_USERINFO | CVAR_ARCHIVE);
 CVAR (Color,	color,					0x40cf00,	CVAR_USERINFO | CVAR_ARCHIVE);
diff --git a/src/d_player.h b/src/d_player.h
index f50db97b16..5affd6913c 100644
--- a/src/d_player.h
+++ b/src/d_player.h
@@ -76,8 +76,6 @@ FPlayerColorSet *P_GetPlayerColorSet(FName classname, int setnum);
 void P_EnumPlayerColorSets(FName classname, TArray<int> *out);
 const char *GetPrintableDisplayName(const PClass *cls);
 
-class player_t;
-
 class APlayerPawn : public AActor
 {
 	DECLARE_CLASS (APlayerPawn, AActor)
@@ -176,7 +174,8 @@ typedef enum
 	PST_LIVE,	// Playing or camping.
 	PST_DEAD,	// Dead on the ground, view follows killer.
 	PST_REBORN,	// Ready to restart/respawn???
-	PST_ENTER	// [BC] Entered the game
+	PST_ENTER,	// [BC] Entered the game
+	PST_GONE	// Player has left the game
 } playerstate_t;
 
 
@@ -398,8 +397,7 @@ public:
 
 	int			inventorytics;
 	BYTE		CurrentPlayerClass;		// class # for this player instance
-	bool		backpack;
-	
+
 	int			frags[MAXPLAYERS];		// kills of other players
 	int			fragcount;				// [RH] Cumulative frags for this player
 	int			lastkilltime;			// [RH] For multikills
diff --git a/src/g_game.cpp b/src/g_game.cpp
index 2058c2df0a..95b0f587d8 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -76,6 +76,7 @@
 #include "d_net.h"
 #include "d_event.h"
 #include "p_acs.h"
+#include "p_effect.h"
 #include "m_joy.h"
 #include "farchive.h"
 #include "r_renderer.h"
@@ -1013,10 +1014,16 @@ void G_Ticker ()
 	// do player reborns if needed
 	for (i = 0; i < MAXPLAYERS; i++)
 	{
-		if (playeringame[i] &&
-			(players[i].playerstate == PST_REBORN || players[i].playerstate == PST_ENTER))
+		if (playeringame[i])
 		{
-			G_DoReborn (i, false);
+			if ((players[i].playerstate == PST_GONE))
+			{
+				G_DoPlayerPop(i);
+			}
+			if ((players[i].playerstate == PST_REBORN || players[i].playerstate == PST_ENTER))
+			{
+				G_DoReborn(i, false);
+			}
 		}
 	}
 
@@ -1658,6 +1665,56 @@ void G_DoReborn (int playernum, bool freshbot)
 	}
 }
 
+//
+// G_DoReborn
+//
+void G_DoPlayerPop(int playernum)
+{
+	playeringame[playernum] = false;
+
+	if (deathmatch)
+	{
+		Printf("%s left the game with %d frags\n",
+			players[playernum].userinfo.GetName(),
+			players[playernum].fragcount);
+	}
+	else
+	{
+		Printf("%s left the game\n", players[playernum].userinfo.GetName());
+	}
+
+	// [RH] Revert each player to their own view if spying through the player who left
+	for (int ii = 0; ii < MAXPLAYERS; ++ii)
+	{
+		if (playeringame[ii] && players[ii].camera == players[playernum].mo)
+		{
+			players[ii].camera = players[ii].mo;
+			if (ii == consoleplayer && StatusBar != NULL)
+			{
+				StatusBar->AttachToPlayer(&players[ii]);
+			}
+		}
+	}
+
+	// [RH] Make the player disappear
+	FBehavior::StaticStopMyScripts(players[playernum].mo);
+	if (players[playernum].mo != NULL)
+	{
+		P_DisconnectEffect(players[playernum].mo);
+		players[playernum].mo->player = NULL;
+		players[playernum].mo->Destroy();
+		if (!(players[playernum].mo->ObjectFlags & OF_EuthanizeMe))
+		{ // We just destroyed a morphed player, so now the original player
+			// has taken their place. Destroy that one too.
+			players[playernum].mo->Destroy();
+		}
+		players[playernum].mo = NULL;
+		players[playernum].camera = NULL;
+	}
+	// [RH] Let the scripts know the player left
+	FBehavior::StaticStartTypedScripts(SCRIPT_Disconnect, NULL, true, playernum);
+}
+
 void G_ScreenShot (char *filename)
 {
 	shotfile = filename;
diff --git a/src/g_game.h b/src/g_game.h
index 051be86b18..4714d8b55d 100644
--- a/src/g_game.h
+++ b/src/g_game.h
@@ -81,6 +81,7 @@ enum EFinishLevelType
 void G_PlayerFinishLevel (int player, EFinishLevelType mode, int flags);
 
 void G_DoReborn (int playernum, bool freshbot);
+void G_DoPlayerPop(int playernum);
 
 // Adds pitch to consoleplayer's viewpitch and clamps it
 void G_AddViewPitch (int look);
diff --git a/src/g_shared/a_pickups.cpp b/src/g_shared/a_pickups.cpp
index acb6224a37..429cb649b8 100644
--- a/src/g_shared/a_pickups.cpp
+++ b/src/g_shared/a_pickups.cpp
@@ -1025,7 +1025,7 @@ void AInventory::Touch (AActor *toucher)
 	for (int i = 0; i < MAXPLAYERS; i++)
 	{
 		if (playeringame[i] && this == players[i].dest)
-    		players[i].dest = NULL;
+			players[i].dest = NULL;
 	}
 }
 
diff --git a/src/hu_scores.cpp b/src/hu_scores.cpp
index 8b9a7d0ad9..fe2735ede9 100644
--- a/src/hu_scores.cpp
+++ b/src/hu_scores.cpp
@@ -49,6 +49,7 @@
 #include "hu_stuff.h"
 #include "gstrings.h"
 #include "d_net.h"
+#include "c_dispatch.h"
 
 // MACROS ------------------------------------------------------------------
 
@@ -117,6 +118,8 @@ int STACK_ARGS compareteams (const void *arg1, const void *arg2)
 	return diff;
 }
 
+bool SB_ForceActive = false;
+
 // PRIVATE DATA DEFINITIONS ------------------------------------------------
 
 // CODE --------------------------------------------------------------------
@@ -492,3 +495,8 @@ int HU_GetRowColor(player_t *player, bool highlight)
 		}
 	}
 }
+
+CCMD (togglescoreboard)
+{
+	SB_ForceActive = !SB_ForceActive;
+}
diff --git a/src/hu_stuff.h b/src/hu_stuff.h
index dc22a2adcc..eb2dc573b5 100644
--- a/src/hu_stuff.h
+++ b/src/hu_stuff.h
@@ -52,6 +52,8 @@ void HU_GetPlayerWidths(int &maxnamewidth, int &maxscorewidth, int &maxiconheigh
 void HU_DrawColorBar(int x, int y, int height, int playernum);
 int HU_GetRowColor(player_t *player, bool hightlight);
 
+extern bool SB_ForceActive;
+
 // Sorting routines
 
 int STACK_ARGS comparepoints(const void *arg1, const void *arg2);
diff --git a/src/i_net.cpp b/src/i_net.cpp
index 3ec9d78813..6fdcb52ba9 100644
--- a/src/i_net.cpp
+++ b/src/i_net.cpp
@@ -110,6 +110,7 @@ const char *neterror (void);
 enum
 {
 	PRE_CONNECT,			// Sent from guest to host for initial connection
+	PRE_KEEPALIVE,
 	PRE_DISCONNECT,			// Sent from guest that aborts the game
 	PRE_ALLHERE,			// Sent from host to guest when everybody has connected
 	PRE_CONACK,				// Sent from host to guest to acknowledge PRE_CONNECT receipt
@@ -548,10 +549,15 @@ bool Host_CheckForConnects (void *userdata)
 				SendConAck (doomcom.numnodes, numplayers);
 			}
 			break;
+
+		case PRE_KEEPALIVE:
+			break;
 		}
 	}
 	if (doomcom.numnodes < numplayers)
 	{
+		// Send message to everyone as a keepalive
+		SendConAck(doomcom.numnodes, numplayers);
 		return false;
 	}
 
@@ -822,6 +828,10 @@ bool Guest_WaitForOthers (void *userdata)
 		}
 	}
 
+	packet.Fake = PRE_FAKE;
+	packet.Message = PRE_KEEPALIVE;
+	PreSend(&packet, 2, &sendaddress[1]);
+
 	return false;
 }
 
diff --git a/src/p_local.h b/src/p_local.h
index 8ba1dd40bb..2dc8c773eb 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -105,6 +105,7 @@ void	P_FallingDamage (AActor *ent);
 void	P_PlayerThink (player_t *player);
 void	P_PredictPlayer (player_t *player);
 void	P_UnPredictPlayer ();
+void	P_PredictionLerpReset();
 
 //
 // P_MOBJ
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index d035e0117b..3e06561a9d 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -252,9 +252,13 @@ void AActor::Serialize (FArchive &arc)
 		<< MinMissileChance
 		<< SpawnFlags
 		<< Inventory
-		<< InventoryID
-		<< id
-		<< FloatBobPhase
+		<< InventoryID;
+	if (SaveVersion < 4513)
+	{
+		SDWORD id;
+		arc << id;
+	}
+	arc << FloatBobPhase
 		<< Translation
 		<< SeeSound
 		<< AttackSound
@@ -4246,6 +4250,12 @@ APlayerPawn *P_SpawnPlayer (FPlayerStart *mthing, int playernum, int flags)
 	if ((unsigned)playernum >= (unsigned)MAXPLAYERS || !playeringame[playernum])
 		return NULL;
 
+	// Old lerp data needs to go
+	if (playernum == consoleplayer)
+	{
+		P_PredictionLerpReset();
+	}
+
 	p = &players[playernum];
 
 	if (p->cls == NULL)
@@ -4358,9 +4368,6 @@ APlayerPawn *P_SpawnPlayer (FPlayerStart *mthing, int playernum, int flags)
 	mobj->pitch = mobj->roll = 0;
 	mobj->health = p->health;
 
-	//Added by MC: Identification (number in the players[MAXPLAYERS] array)
-    mobj->id = playernum;
-
 	// [RH] Set player sprite based on skin
 	if (!(mobj->flags4 & MF4_NOSKIN))
 	{
diff --git a/src/p_teleport.cpp b/src/p_teleport.cpp
index b64c04a5ae..60308d8ed7 100644
--- a/src/p_teleport.cpp
+++ b/src/p_teleport.cpp
@@ -328,7 +328,6 @@ static AActor *SelectTeleDest (int tid, int tag, bool norandom)
 bool EV_Teleport (int tid, int tag, line_t *line, int side, AActor *thing, bool fog,
 				  bool sourceFog, bool keepOrientation, bool haltVelocity, bool keepHeight)
 {
-	bool predicting = (thing->player && (thing->player->cheats & CF_PREDICTING));
 
 	AActor *searcher;
 	fixed_t z;
@@ -341,6 +340,7 @@ bool EV_Teleport (int tid, int tag, line_t *line, int side, AActor *thing, bool
 	{ // Teleport function called with an invalid actor
 		return false;
 	}
+	bool predicting = (thing->player && (thing->player->cheats & CF_PREDICTING));
 	if (thing->flags2 & MF2_NOTELEPORT)
 	{
 		return false;
diff --git a/src/p_user.cpp b/src/p_user.cpp
index 7b049a2df7..6595f7309a 100644
--- a/src/p_user.cpp
+++ b/src/p_user.cpp
@@ -63,6 +63,27 @@ static FRandom pr_skullpop ("SkullPop");
 // Variables for prediction
 CVAR (Bool, cl_noprediction, false, CVAR_ARCHIVE|CVAR_GLOBALCONFIG)
 CVAR(Bool, cl_predict_specials, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+
+CUSTOM_CVAR(Float, cl_predict_lerpscale, 0.05f, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+{
+	P_PredictionLerpReset();
+}
+CUSTOM_CVAR(Float, cl_predict_lerpthreshold, 2.00f, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
+{
+	if (self < 0.1f)
+		self = 0.1f;
+	P_PredictionLerpReset();
+}
+
+struct PredictPos
+{
+	int gametic;
+	FVector3 point;
+	fixed_t pitch;
+	fixed_t yaw;
+} static PredictionLerpFrom, PredictionLerpResult, PredictionLast;
+static int PredictionLerptics;
+
 static player_t PredictionPlayerBackup;
 static BYTE PredictionActorBackup[sizeof(AActor)];
 static TArray<sector_t *> PredictionTouchingSectorsBackup;
@@ -240,7 +261,6 @@ player_t::player_t()
   health(0),
   inventorytics(0),
   CurrentPlayerClass(0),
-  backpack(0),
   fragcount(0),
   lastkilltime(0),
   multicount(0),
@@ -341,7 +361,6 @@ player_t &player_t::operator=(const player_t &p)
 	health = p.health;
 	inventorytics = p.inventorytics;
 	CurrentPlayerClass = p.CurrentPlayerClass;
-	backpack = p.backpack;
 	memcpy(frags, &p.frags, sizeof(frags));
 	fragcount = p.fragcount;
 	lastkilltime = p.lastkilltime;
@@ -2638,6 +2657,22 @@ void P_PlayerThink (player_t *player)
 	}
 }
 
+void P_PredictionLerpReset()
+{
+	PredictionLerptics = PredictionLast.gametic = PredictionLerpFrom.gametic = PredictionLerpResult.gametic = 0;
+}
+
+bool P_LerpCalculate(FVector3 from, FVector3 to, FVector3 &result, float scale)
+{
+	result = to - from;
+	result *= scale;
+	result = result + from;
+	FVector3 delta = result - to;
+
+	// As a fail safe, assume extrapolation is the threshold.
+	return (delta.LengthSquared() > cl_predict_lerpthreshold && scale <= 1.00f);
+}
+
 void P_PredictPlayer (player_t *player)
 {
 	int maxtic;
@@ -2665,8 +2700,8 @@ void P_PredictPlayer (player_t *player)
 	// Save original values for restoration later
 	PredictionPlayerBackup = *player;
 
-	AActor *act = player->mo;
-	memcpy (PredictionActorBackup, &act->x, sizeof(AActor)-((BYTE *)&act->x-(BYTE *)act));
+	APlayerPawn *act = player->mo;
+	memcpy(PredictionActorBackup, &act->x, sizeof(APlayerPawn) - ((BYTE *)&act->x - (BYTE *)act));
 
 	act->flags &= ~MF_PICKUP;
 	act->flags2 &= ~MF2_PUSHWALL;
@@ -2723,7 +2758,8 @@ void P_PredictPlayer (player_t *player)
 	}
 	act->BlockNode = NULL;
 
-	bool NoInterpolateOld = R_GetViewInterpolationStatus();
+	// Values too small to be usable for lerping can be considered "off".
+	bool CanLerp = (!(cl_predict_lerpscale < 0.01f) && (ticdup == 1)), DoLerp = false, NoInterpolateOld = R_GetViewInterpolationStatus();
 	for (int i = gametic; i < maxtic; ++i)
 	{
 		if (!NoInterpolateOld)
@@ -2732,6 +2768,47 @@ void P_PredictPlayer (player_t *player)
 		player->cmd = localcmds[i % LOCALCMDTICS];
 		P_PlayerThink (player);
 		player->mo->Tick ();
+
+		if (CanLerp && PredictionLast.gametic > 0 && i == PredictionLast.gametic && !NoInterpolateOld)
+		{
+			// Z is not compared as lifts will alter this with no apparent change
+			DoLerp = (PredictionLast.point.X != FIXED2FLOAT(player->mo->x) ||
+				PredictionLast.point.Y != FIXED2FLOAT(player->mo->y));
+		}
+	}
+
+	if (CanLerp)
+	{
+		if (NoInterpolateOld)
+			P_PredictionLerpReset();
+
+		else if (DoLerp)
+		{
+			// If lerping is already in effect, use the previous camera postion so the view doesn't suddenly snap
+			PredictionLerpFrom = (PredictionLerptics == 0) ? PredictionLast : PredictionLerpResult;
+			PredictionLerptics = 1;
+		}
+
+		PredictionLast.gametic = maxtic - 1;
+		PredictionLast.point.X = FIXED2FLOAT(player->mo->x);
+		PredictionLast.point.Y = FIXED2FLOAT(player->mo->y);
+		PredictionLast.point.Z = FIXED2FLOAT(player->mo->z);
+
+		if (PredictionLerptics > 0)
+		{
+			if (PredictionLerpFrom.gametic > 0 &&
+				P_LerpCalculate(PredictionLerpFrom.point, PredictionLast.point, PredictionLerpResult.point, (float)PredictionLerptics * cl_predict_lerpscale))
+			{
+				PredictionLerptics++;
+				player->mo->x = FLOAT2FIXED(PredictionLerpResult.point.X);
+				player->mo->y = FLOAT2FIXED(PredictionLerpResult.point.Y);
+				player->mo->z = FLOAT2FIXED(PredictionLerpResult.point.Z);
+			}
+			else
+			{
+				PredictionLerptics = 0;
+			}
+		}
 	}
 }
 
@@ -2744,9 +2821,12 @@ void P_UnPredictPlayer ()
 	if (player->cheats & CF_PREDICTING)
 	{
 		unsigned int i;
-		AActor *act = player->mo;
+		APlayerPawn *act = player->mo;
 		AActor *savedcamera = player->camera;
 
+		TObjPtr<AInventory> InvSel = act->InvSel;
+		int inventorytics = player->inventorytics;
+
 		*player = PredictionPlayerBackup;
 
 		// Restore the camera instead of using the backup's copy, because spynext/prev
@@ -2754,7 +2834,7 @@ void P_UnPredictPlayer ()
 		player->camera = savedcamera;
 
 		act->UnlinkFromWorld();
-		memcpy(&act->x, PredictionActorBackup, sizeof(AActor)-((BYTE *)&act->x - (BYTE *)act));
+		memcpy(&act->x, PredictionActorBackup, sizeof(APlayerPawn) - ((BYTE *)&act->x - (BYTE *)act));
 
 		// The blockmap ordering needs to remain unchanged, too.
 		// Restore sector links and refrences.
@@ -2859,6 +2939,9 @@ void P_UnPredictPlayer ()
 			}
 			block = block->NextBlock;
 		}
+
+		act->InvSel = InvSel;
+		player->inventorytics = inventorytics;
 	}
 }
 
@@ -2889,9 +2972,13 @@ void player_t::Serialize (FArchive &arc)
 		<< vely
 		<< centering
 		<< health
-		<< inventorytics
-		<< backpack
-		<< fragcount
+		<< inventorytics;
+	if (SaveVersion < 4513)
+	{
+		bool backpack;
+		arc << backpack;
+	}
+	arc << fragcount
 		<< spreecount
 		<< multicount
 		<< lastkilltime
diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index 65888d0d56..d17bbc75ff 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -1768,6 +1768,7 @@ enum SIX_Flags
 	SIXF_SETTARGET				= 1 << 20,
 	SIXF_SETTRACER				= 1 << 21,
 	SIXF_NOPOINTERS				= 1 << 22,
+	SIXF_ORIGINATOR				= 1 << 23,
 };
 
 static bool InitSpawnedItem(AActor *self, AActor *mo, int flags)
@@ -1803,11 +1804,13 @@ static bool InitSpawnedItem(AActor *self, AActor *mo, int flags)
 	{
 		mo->pitch = self->pitch;
 	}
-	while (originator && originator->isMissile())
+	if (!(flags & SIXF_ORIGINATOR))
 	{
-		originator = originator->target;
-	}
-
+		while (originator && originator->isMissile())
+		{
+			originator = originator->target;
+		}
+	}	
 	if (flags & SIXF_TELEFRAG) 
 	{
 		P_TeleportMove(mo, mo->x, mo->y, mo->z, true);
@@ -3278,18 +3281,19 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckLOF)
 
 enum JLOS_flags
 {
-	JLOSF_PROJECTILE=1,
-	JLOSF_NOSIGHT=2,
-	JLOSF_CLOSENOFOV=4,
-	JLOSF_CLOSENOSIGHT=8,
-	JLOSF_CLOSENOJUMP=16,
-	JLOSF_DEADNOJUMP=32,
-	JLOSF_CHECKMASTER=64,
-	JLOSF_TARGETLOS=128,
-	JLOSF_FLIPFOV=256,
-	JLOSF_ALLYNOJUMP=512,
-	JLOSF_COMBATANTONLY=1024,
-	JLOSF_NOAUTOAIM=2048,
+	JLOSF_PROJECTILE =		1,
+	JLOSF_NOSIGHT =			1 << 1,
+	JLOSF_CLOSENOFOV =		1 << 2,
+	JLOSF_CLOSENOSIGHT =	1 << 3,
+	JLOSF_CLOSENOJUMP =		1 << 4,
+	JLOSF_DEADNOJUMP =		1 << 5,
+	JLOSF_CHECKMASTER =		1 << 6,
+	JLOSF_TARGETLOS =		1 << 7,
+	JLOSF_FLIPFOV =			1 << 8,
+	JLOSF_ALLYNOJUMP =		1 << 9,
+	JLOSF_COMBATANTONLY =	1 << 10,
+	JLOSF_NOAUTOAIM =		1 << 11,
+	JLOSF_CHECKTRACER =		1 << 12,
 };
 
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_JumpIfTargetInLOS)
@@ -3314,9 +3318,9 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_JumpIfTargetInLOS)
 		{
 			target = self->master;
 		}
-		else if (self->flags & MF_MISSILE && (flags & JLOSF_PROJECTILE))
+		else if ((self->flags & MF_MISSILE && (flags & JLOSF_PROJECTILE)) || (flags & JLOSF_CHECKTRACER))
 		{
-			if (self->flags2 & MF2_SEEKERMISSILE)
+			if ((self->flags2 & MF2_SEEKERMISSILE) || (flags & JLOSF_CHECKTRACER))
 				target = self->tracer;
 			else
 				target = NULL;
@@ -5002,7 +5006,7 @@ static void DoKill(AActor *killtarget, AActor *self, FName damagetype, int flags
 		//since that's the whole point of it.
 		if ((!(killtarget->flags2 & MF2_INVULNERABLE) || (flags & KILS_FOILINVUL)) && !(killtarget->flags5 & MF5_NODAMAGE))
 		{
-			P_ExplodeMissile(self->target, NULL, NULL);
+			P_ExplodeMissile(killtarget, NULL, NULL);
 		}
 	}
 	if (!(flags & KILS_NOMONSTERS))
@@ -5112,9 +5116,9 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_KillSiblings)
 
 enum RMVF_flags
 {
-	RMVF_MISSILES = 1 << 0,
+	RMVF_MISSILES	= 1 << 0,
 	RMVF_NOMONSTERS = 1 << 1,
-	RMVF_MISC = 1 << 2,
+	RMVF_MISC		= 1 << 2,
 	RMVF_EVERYTHING = 1 << 3,
 };
 
diff --git a/src/version.h b/src/version.h
index 45ecb794a1..e6e372d4c4 100644
--- a/src/version.h
+++ b/src/version.h
@@ -76,7 +76,7 @@ const char *GetVersionString();
 
 // Use 4500 as the base git save version, since it's higher than the
 // SVN revision ever got.
-#define SAVEVER 4512
+#define SAVEVER 4513
 
 #define SAVEVERSTRINGIFY2(x) #x
 #define SAVEVERSTRINGIFY(x) SAVEVERSTRINGIFY2(x)
diff --git a/wadsrc/static/actors/constants.txt b/wadsrc/static/actors/constants.txt
index 57de8e6ad8..da289dc50e 100644
--- a/wadsrc/static/actors/constants.txt
+++ b/wadsrc/static/actors/constants.txt
@@ -1,396 +1,401 @@
-
-// Flags for A_PainAttack
-const int PAF_NOSKULLATTACK = 1;
-const int PAF_AIMFACING = 2;
-const int PAF_NOTARGET = 4;
-
-// Flags for A_VileAttack
-const int VAF_DMGTYPEAPPLYTODIRECT = 1;
-
-// Flags for A_Saw
-const int SF_NORANDOM = 1;
-const int SF_RANDOMLIGHTMISS = 2;
-const int SF_RANDOMLIGHTHIT = 4;
-const int SF_RANDOMLIGHTBOTH = 6;
-const int SF_NOUSEAMMOMISS = 8;
-const int SF_NOUSEAMMO = 16;
-const int SF_NOPULLIN = 32;
-const int SF_NOTURN = 64;
-
-// Flags for A_CustomMissile
-const int CMF_AIMOFFSET = 1;
-const int CMF_AIMDIRECTION = 2;
-const int CMF_TRACKOWNER = 4;
-const int CMF_CHECKTARGETDEAD = 8;
-const int CMF_ABSOLUTEPITCH = 16;
-const int CMF_OFFSETPITCH = 32;
-const int CMF_SAVEPITCH = 64;
-const int CMF_ABSOLUTEANGLE = 128;
-
-// Flags for A_CustomBulletAttack
-const int CBAF_AIMFACING = 1;
-const int CBAF_NORANDOM = 2;
-const int CBAF_EXPLICITANGLE = 4;
-const int CBAF_NOPITCH = 8;
-const int CBAF_NORANDOMPUFFZ = 16;
-
-// Flags for A_GunFlash
-const int GFF_NOEXTCHANGE = 1;
-
-// Flags for A_FireBullets
-const int FBF_USEAMMO = 1;
-const int FBF_NORANDOM = 2;
-const int FBF_EXPLICITANGLE = 4;
-const int FBF_NOPITCH = 8;
-const int FBF_NOFLASH = 16;
-const int FBF_NORANDOMPUFFZ = 32;
-
-// Flags for A_SpawnItemEx
-const int SXF_TRANSFERTRANSLATION =		1 << 0;
-const int SXF_ABSOLUTEPOSITION =		1 << 1;
-const int SXF_ABSOLUTEANGLE =			1 << 2;
-const int SXF_ABSOLUTEMOMENTUM =		1 << 3;	//Since "momentum" is declared to be deprecated in the expressions, for compatibility
-const int SXF_ABSOLUTEVELOCITY =		1 << 3;	//purposes, this was made. It does the same thing though. Do not change the value.
-const int SXF_SETMASTER =				1 << 4;
-const int SXF_NOCHECKPOSITION =			1 << 5;
-const int SXF_TELEFRAG =				1 << 6;
-const int SXF_CLIENTSIDE =				1 << 7;	// only used by Skulltag
-const int SXF_TRANSFERAMBUSHFLAG =		1 << 8;
-const int SXF_TRANSFERPITCH =			1 << 9;
-const int SXF_TRANSFERPOINTERS =		1 << 10;
-const int SXF_USEBLOODCOLOR =			1 << 11;
-const int SXF_CLEARCALLERTID =			1 << 12;
-const int SXF_MULTIPLYSPEED =			1 << 13;
-const int SXF_TRANSFERSCALE =			1 << 14;
-const int SXF_TRANSFERSPECIAL =			1 << 15;
-const int SXF_CLEARCALLERSPECIAL =		1 << 16;
-const int SXF_TRANSFERSTENCILCOL =		1 << 17;
-const int SXF_TRANSFERALPHA =			1 << 18;
-const int SXF_TRANSFERRENDERSTYLE =		1 << 19;
-const int SXF_SETTARGET =				1 << 20;
-const int SXF_SETTRACER =				1 << 21;
-const int SXF_NOPOINTERS =				1 << 22;
-
-// Flags for A_Chase
-const int CHF_FASTCHASE = 1;
-const int CHF_NOPLAYACTIVE = 2;
-const int CHF_NIGHTMAREFAST = 4;
-const int CHF_RESURRECT = 8;
-const int CHF_DONTMOVE = 16;
-
-// Flags for A_LookEx
-const int LOF_NOSIGHTCHECK = 1;
-const int LOF_NOSOUNDCHECK = 2;
-const int LOF_DONTCHASEGOAL = 4;
-const int LOF_NOSEESOUND = 8;
-const int LOF_FULLVOLSEESOUND = 16;
-const int LOF_NOJUMP = 32;
-
-// Flags for A_Respawn
-const int RSF_FOG = 1;
-const int RSF_KEEPTARGET = 2;
-const int RSF_TELEFRAG = 4;
-
-// Flags for A_JumpIfTargetInLOS and A_JumpIfInTargetLOS
-const int JLOSF_PROJECTILE = 1;
-const int JLOSF_NOSIGHT = 2;
-const int JLOSF_CLOSENOFOV = 4;
-const int JLOSF_CLOSENOSIGHT = 8;
-const int JLOSF_CLOSENOJUMP = 16;
-const int JLOSF_DEADNOJUMP = 32;
-const int JLOSF_CHECKMASTER = 64;
-const int JLOSF_TARGETLOS = 128;
-const int JLOSF_FLIPFOV = 256;
-const int JLOSF_ALLYNOJUMP = 512;
-const int JLOSF_COMBATANTONLY = 1024;
-const int JLOSF_NOAUTOAIM = 2048;
-
-// Flags for A_ChangeVelocity
-const int CVF_RELATIVE = 1;
-const int CVF_REPLACE = 2;
-
-// Flags for A_WeaponReady
-const int WRF_NOBOB = 1;
-const int WRF_NOSWITCH = 2;
-const int WRF_NOPRIMARY = 4;
-const int WRF_NOSECONDARY = 8;
-const int WRF_NOFIRE = WRF_NOPRIMARY | WRF_NOSECONDARY;
-const int WRF_ALLOWRELOAD = 16;
-const int WRF_ALLOWZOOM = 32;
-const int WRF_DISABLESWITCH = 64;
-
-// Morph constants
-const int MRF_ADDSTAMINA = 1;
-const int MRF_FULLHEALTH = 2;
-const int MRF_UNDOBYTOMEOFPOWER = 4;
-const int MRF_UNDOBYCHAOSDEVICE = 8;
-const int MRF_FAILNOTELEFRAG = 16;
-const int MRF_FAILNOLAUGH = 32;
-const int MRF_WHENINVULNERABLE = 64;
-const int MRF_LOSEACTUALWEAPON = 128;
-const int MRF_NEWTIDBEHAVIOUR = 256;
-const int MRF_UNDOBYDEATH = 512;
-const int MRF_UNDOBYDEATHFORCED = 1024;
-const int MRF_UNDOBYDEATHSAVES = 2048;
-
-// Flags for A_RailAttack and A_CustomRailgun
-const int RGF_SILENT = 1;
-const int RGF_NOPIERCING = 2;
-const int RGF_EXPLICITANGLE = 4;
-const int RGF_FULLBRIGHT = 8;
-const int RGF_CENTERZ = 16;
-
-// Flags for A_Mushroom
-const int MSF_Standard = 0;
-const int MSF_Classic = 1;
-const int MSF_DontHurt = 2;
-
-// Flags for A_Explode
-const int XF_HURTSOURCE = 1;
-const int XF_NOTMISSILE = 4;
-
-// Flags for A_RadiusThrust
-const int RTF_AFFECTSOURCE = 1;
-const int RTF_NOIMPACTDAMAGE = 2;
-const int RTF_NOTMISSILE = 4;
-
-// Flags for A_Blast
-const int BF_USEAMMO = 1;
-const int BF_DONTWARN = 2;
-const int BF_AFFECTBOSSES = 4;
-const int BF_NOIMPACTDAMAGE = 8;
-
-// Flags for A_SeekerMissile
-const int SMF_LOOK = 1;
-const int SMF_PRECISE = 2;
-const int SMF_CURSPEED = 4;
-
-// Flags for A_CustomPunch
-const int CPF_USEAMMO = 1;
-const int CPF_DAGGER = 2;
-const int CPF_PULLIN = 4;
-const int CPF_NORANDOMPUFFZ = 8;
-
-// Flags for A_CustomMissile
-const int FPF_AIMATANGLE = 1;
-const int FPF_TRANSFERTRANSLATION = 2;
-
-// Flags for A_Teleport
-const int TF_TELEFRAG = 1;const int TF_RANDOMDECIDE = 2;
-
-// Flags for A_WolfAttack
-const int WAF_NORANDOM = 1;
-const int WAF_USEPUFF = 2;
-
-// Flags for A_RadiusGive
-enum
-{
-	RGF_GIVESELF	=   1,
-	RGF_PLAYERS		=   2,
-	RGF_MONSTERS	=   4,
-	RGF_OBJECTS		=   8,
-	RGF_VOODOO		=  16,
-	RGF_CORPSES		=  32,
-	RGF_NOTARGET	=  64,
-	RGF_NOTRACER	= 128,
-	RGF_NOMASTER	= 256,
-	RGF_CUBE		= 512,
-};
-
-// Activation flags
-enum
-{
-	THINGSPEC_Default = 0,
-	THINGSPEC_ThingActs = 1,
-	THINGSPEC_ThingTargets = 2,
-	THINGSPEC_TriggerTargets = 4,
-	THINGSPEC_MonsterTrigger = 8,
-	THINGSPEC_MissileTrigger = 16,
-	THINGSPEC_ClearSpecial = 32,
-	THINGSPEC_NoDeathSpecial = 64,
-	THINGSPEC_TriggerActs = 128,
-};
-// Shorter aliases for same
-const int AF_Default = 0;
-const int AF_ThingActs = 1;
-const int AF_ThingTargets = 2;
-const int AF_TriggerTargets = 4;
-const int AF_MonsterTrigger = 8;
-const int AF_MissileTrigger = 16;
-const int AF_ClearSpecial = 32;
-const int AF_NoDeathSpecial = 64;
-const int AF_TriggerActs = 128;
-
-// Flags for A_TakeInventory and A_TakeFromTarget
-const int TIF_NOTAKEINFINITE = 1;
-
-// constants for A_PlaySound
-enum
-{
-	CHAN_AUTO = 0,
-	CHAN_WEAPON = 1,
-	CHAN_VOICE = 2,
-	CHAN_ITEM = 3,
-	CHAN_BODY = 4,
-	CHAN_5 = 5,
-	CHAN_6 = 6,
-	CHAN_7 = 7,
-	
-	// modifier flags
-	CHAN_LISTENERZ = 8,
-	CHAN_MAYBE_LOCAL = 16,
-	CHAN_UI = 32,
-	CHAN_NOPAUSE = 64
-};
-
-// sound attenuation values
-const float ATTN_NONE = 0;
-const float ATTN_NORM = 1;
-const float ATTN_IDLE = 1.001;
-const float ATTN_STATIC = 3;
-
-// For SetPlayerProprty action special
-Const Int PROP_FROZEN = 0;
-Const Int PROP_NOTARGET = 1;
-Const Int PROP_INSTANTWEAPONSWITCH = 2;
-Const Int PROP_FLY = 3;
-Const Int PROP_TOTALLYFROZEN = 4;
-Const Int PROP_INVULNERABILITY  = 5; // (Deprecated)
-Const Int PROP_STRENGTH = 6; // (Deprecated)
-Const Int PROP_INVISIBILITY = 7; // (Deprecated)
-Const Int PROP_RADIATIONSUIT = 8; // (Deprecated)
-Const Int PROP_ALLMAP = 9; // (Deprecated)
-Const Int PROP_INFRARED = 10; // (Deprecated)
-Const Int PROP_WEAPONLEVEL2 = 11; // (Deprecated)
-Const Int PROP_FLIGHT = 12; // (Deprecated)
-Const Int PROP_SPEED = 15; // (Deprecated)
-Const Int PROP_BUDDHA = 16;
-
-// Line_SetBlocking
-Const Int BLOCKF_CREATURES = 1;
-Const Int BLOCKF_MONSTERS = 2;
-Const Int BLOCKF_PLAYERS = 4;
-Const Int BLOCKF_FLOATERS = 8;
-Const Int BLOCKF_PROJECTILES = 16;
-Const Int BLOCKF_EVERYTHING = 32;
-Const Int BLOCKF_RAILING = 64;
-Const Int BLOCKF_USE = 128;
-
-// Pointer constants, bitfield-enabled
-
-Const Int AAPTR_DEFAULT = 0;
-Const Int AAPTR_NULL = 0x1;
-Const Int AAPTR_TARGET = 0x2;
-Const Int AAPTR_MASTER = 0x4;
-Const Int AAPTR_TRACER = 0x8;
-
-Const Int AAPTR_PLAYER_GETTARGET = 0x10;
-Const Int AAPTR_PLAYER_GETCONVERSATION = 0x20;
-
-Const Int AAPTR_PLAYER1 = 0x40;
-Const Int AAPTR_PLAYER2 = 0x80;
-Const Int AAPTR_PLAYER3 = 0x100;
-Const Int AAPTR_PLAYER4 = 0x200;
-Const Int AAPTR_PLAYER5 = 0x400;
-Const Int AAPTR_PLAYER6 = 0x800;
-Const Int AAPTR_PLAYER7 = 0x1000;
-Const Int AAPTR_PLAYER8 = 0x2000;
-
-Const Int AAPTR_FRIENDPLAYER = 0x4000;
-Const Int AAPTR_LINETARGET = 0x8000;
-
-// Pointer operation flags
-
-Const Int PTROP_UNSAFETARGET = 1;
-Const Int PTROP_UNSAFEMASTER = 2;
-Const Int PTROP_NOSAFEGUARDS = PTROP_UNSAFETARGET|PTROP_UNSAFEMASTER;
-
-
-// Flags for A_Warp
-
-Const Int WARPF_ABSOLUTEOFFSET = 0x1;
-Const Int WARPF_ABSOLUTEANGLE = 0x2;
-Const Int WARPF_USECALLERANGLE = 0x4;
-Const Int WARPF_NOCHECKPOSITION = 0x8;
-Const Int WARPF_INTERPOLATE = 0x10;
-Const Int WARPF_WARPINTERPOLATION = 0x20;
-Const Int WARPF_COPYINTERPOLATION = 0x40;
-Const Int WARPF_STOP = 0x80;
-Const Int WARPF_TOFLOOR = 0x100;
-Const Int WARPF_TESTONLY = 0x200;
-Const Int WAPRF_ABSOLUTEPOSITION = 0x400;
-
-// flags for A_SetPitch/SetAngle
-const int SPF_FORCECLAMP = 1;
-const int SPF_INTERPOLATE = 2;
-
-
-// flags for A_CheckLOF
-
-enum
-{
-	CLOFF_NOAIM_VERT =			0x1,
-	CLOFF_NOAIM_HORZ =			0x2,
-
-	CLOFF_JUMPENEMY =			0x4,
-	CLOFF_JUMPFRIEND =			0x8,
-	CLOFF_JUMPOBJECT =			0x10,
-	CLOFF_JUMPNONHOSTILE =		0x20,
-
-	CLOFF_SKIPENEMY =			0x40,
-	CLOFF_SKIPFRIEND =			0x80,
-	CLOFF_SKIPOBJECT =			0x100,
-	CLOFF_SKIPNONHOSTILE =		0x200,
-
-	CLOFF_MUSTBESHOOTABLE =		0x400,
-
-	CLOFF_SKIPTARGET =			0x800,
-	CLOFF_ALLOWNULL =			0x1000,
-	CLOFF_CHECKPARTIAL =		0x2000,
-
-	CLOFF_MUSTBEGHOST =			0x4000,
-	CLOFF_IGNOREGHOST =			0x8000,
-	
-	CLOFF_MUSTBESOLID =			0x10000,
-	CLOFF_BEYONDTARGET =		0x20000,
-
-	CLOFF_FROMBASE =			0x40000,
-	CLOFF_MUL_HEIGHT =			0x80000,
-	CLOFF_MUL_WIDTH =			0x100000,
-
-	CLOFF_JUMP_ON_MISS =		0x200000,
-	CLOFF_AIM_VERT_NOOFFSET =	0x400000,
-
-	CLOFF_SKIPOBSTACLES = CLOFF_SKIPENEMY|CLOFF_SKIPFRIEND|CLOFF_SKIPOBJECT|CLOFF_SKIPNONHOSTILE,
-	CLOFF_NOAIM = CLOFF_NOAIM_VERT|CLOFF_NOAIM_HORZ
-};
-
-// Flags for A_Kill (Master/Target/Tracer/Children/Siblings) series
-
-const int KILS_FOILINVUL =		1;
-const int KILS_KILLMISSILES =	2;
-const int KILS_NOMONSTERS =		4;
-
-// Flags for A_Damage (Master/Target/Tracer/Children/Siblings/Self) series
-const int DMSS_FOILINVUL =		1;
-const int DMSS_AFFECTARMOR =	2;
-const int DMSS_KILL =			4;
-const int DMSS_NOFACTOR =	8;
-
-// Flags for A_AlertMonsters
-const int AMF_TARGETEMITTER = 1;
-const int AMF_TARGETNONPLAYER = 2;
-const int AMF_EMITFROMTARGET = 4;
-
-// Flags for A_Remove*
-enum
-{
-	RMVF_MISSILES =			1 << 0,
-	RMVF_NOMONSTERS =		1 << 1,
-	RMVF_MISC =				1 << 2,
-	RMVF_EVERYTHING =		1 << 3
-};
-
-
-// This is only here to provide one global variable for testing.
-native int testglobalvar;
+
+// Flags for A_PainAttack
+const int PAF_NOSKULLATTACK = 1;
+const int PAF_AIMFACING = 2;
+const int PAF_NOTARGET = 4;
+
+// Flags for A_VileAttack
+const int VAF_DMGTYPEAPPLYTODIRECT = 1;
+
+// Flags for A_Saw
+const int SF_NORANDOM = 1;
+const int SF_RANDOMLIGHTMISS = 2;
+const int SF_RANDOMLIGHTHIT = 4;
+const int SF_RANDOMLIGHTBOTH = 6;
+const int SF_NOUSEAMMOMISS = 8;
+const int SF_NOUSEAMMO = 16;
+const int SF_NOPULLIN = 32;
+const int SF_NOTURN = 64;
+
+// Flags for A_CustomMissile
+const int CMF_AIMOFFSET = 1;
+const int CMF_AIMDIRECTION = 2;
+const int CMF_TRACKOWNER = 4;
+const int CMF_CHECKTARGETDEAD = 8;
+const int CMF_ABSOLUTEPITCH = 16;
+const int CMF_OFFSETPITCH = 32;
+const int CMF_SAVEPITCH = 64;
+const int CMF_ABSOLUTEANGLE = 128;
+
+// Flags for A_CustomBulletAttack
+const int CBAF_AIMFACING = 1;
+const int CBAF_NORANDOM = 2;
+const int CBAF_EXPLICITANGLE = 4;
+const int CBAF_NOPITCH = 8;
+const int CBAF_NORANDOMPUFFZ = 16;
+
+// Flags for A_GunFlash
+const int GFF_NOEXTCHANGE = 1;
+
+// Flags for A_FireBullets
+const int FBF_USEAMMO = 1;
+const int FBF_NORANDOM = 2;
+const int FBF_EXPLICITANGLE = 4;
+const int FBF_NOPITCH = 8;
+const int FBF_NOFLASH = 16;
+const int FBF_NORANDOMPUFFZ = 32;
+
+// Flags for A_SpawnItemEx
+const int SXF_TRANSFERTRANSLATION =		1 << 0;
+const int SXF_ABSOLUTEPOSITION =		1 << 1;
+const int SXF_ABSOLUTEANGLE =			1 << 2;
+const int SXF_ABSOLUTEMOMENTUM =		1 << 3;	//Since "momentum" is declared to be deprecated in the expressions, for compatibility
+const int SXF_ABSOLUTEVELOCITY =		1 << 3;	//purposes, this was made. It does the same thing though. Do not change the value.
+const int SXF_SETMASTER =				1 << 4;
+const int SXF_NOCHECKPOSITION =			1 << 5;
+const int SXF_TELEFRAG =				1 << 6;
+const int SXF_CLIENTSIDE =				1 << 7;	// only used by Skulltag
+const int SXF_TRANSFERAMBUSHFLAG =		1 << 8;
+const int SXF_TRANSFERPITCH =			1 << 9;
+const int SXF_TRANSFERPOINTERS =		1 << 10;
+const int SXF_USEBLOODCOLOR =			1 << 11;
+const int SXF_CLEARCALLERTID =			1 << 12;
+const int SXF_MULTIPLYSPEED =			1 << 13;
+const int SXF_TRANSFERSCALE =			1 << 14;
+const int SXF_TRANSFERSPECIAL =			1 << 15;
+const int SXF_CLEARCALLERSPECIAL =		1 << 16;
+const int SXF_TRANSFERSTENCILCOL =		1 << 17;
+const int SXF_TRANSFERALPHA =			1 << 18;
+const int SXF_TRANSFERRENDERSTYLE =		1 << 19;
+const int SXF_SETTARGET =				1 << 20;
+const int SXF_SETTRACER =				1 << 21;
+const int SXF_NOPOINTERS =				1 << 22;
+const int SXF_ORIGINATOR =				1 << 23;
+
+// Flags for A_Chase
+const int CHF_FASTCHASE = 1;
+const int CHF_NOPLAYACTIVE = 2;
+const int CHF_NIGHTMAREFAST = 4;
+const int CHF_RESURRECT = 8;
+const int CHF_DONTMOVE = 16;
+
+// Flags for A_LookEx
+const int LOF_NOSIGHTCHECK = 1;
+const int LOF_NOSOUNDCHECK = 2;
+const int LOF_DONTCHASEGOAL = 4;
+const int LOF_NOSEESOUND = 8;
+const int LOF_FULLVOLSEESOUND = 16;
+const int LOF_NOJUMP = 32;
+
+// Flags for A_Respawn
+const int RSF_FOG = 1;
+const int RSF_KEEPTARGET = 2;
+const int RSF_TELEFRAG = 4;
+
+// Flags for A_JumpIfTargetInLOS and A_JumpIfInTargetLOS
+enum
+{
+	JLOSF_PROJECTILE =		1,
+	JLOSF_NOSIGHT =			1 << 1,
+	JLOSF_CLOSENOFOV =		1 << 2,
+	JLOSF_CLOSENOSIGHT =	1 << 3,
+	JLOSF_CLOSENOJUMP =		1 << 4,
+	JLOSF_DEADNOJUMP =		1 << 5,
+	JLOSF_CHECKMASTER =		1 << 6,
+	JLOSF_TARGETLOS =		1 << 7,
+	JLOSF_FLIPFOV =			1 << 8,
+	JLOSF_ALLYNOJUMP =		1 << 9,
+	JLOSF_COMBATANTONLY =	1 << 10,
+	JLOSF_NOAUTOAIM =		1 << 11,
+	JLOSF_CHECKTRACER =		1 << 12,
+};
+
+// Flags for A_ChangeVelocity
+const int CVF_RELATIVE = 1;
+const int CVF_REPLACE = 2;
+
+// Flags for A_WeaponReady
+const int WRF_NOBOB = 1;
+const int WRF_NOSWITCH = 2;
+const int WRF_NOPRIMARY = 4;
+const int WRF_NOSECONDARY = 8;
+const int WRF_NOFIRE = WRF_NOPRIMARY | WRF_NOSECONDARY;
+const int WRF_ALLOWRELOAD = 16;
+const int WRF_ALLOWZOOM = 32;
+const int WRF_DISABLESWITCH = 64;
+
+// Morph constants
+const int MRF_ADDSTAMINA = 1;
+const int MRF_FULLHEALTH = 2;
+const int MRF_UNDOBYTOMEOFPOWER = 4;
+const int MRF_UNDOBYCHAOSDEVICE = 8;
+const int MRF_FAILNOTELEFRAG = 16;
+const int MRF_FAILNOLAUGH = 32;
+const int MRF_WHENINVULNERABLE = 64;
+const int MRF_LOSEACTUALWEAPON = 128;
+const int MRF_NEWTIDBEHAVIOUR = 256;
+const int MRF_UNDOBYDEATH = 512;
+const int MRF_UNDOBYDEATHFORCED = 1024;
+const int MRF_UNDOBYDEATHSAVES = 2048;
+
+// Flags for A_RailAttack and A_CustomRailgun
+const int RGF_SILENT = 1;
+const int RGF_NOPIERCING = 2;
+const int RGF_EXPLICITANGLE = 4;
+const int RGF_FULLBRIGHT = 8;
+const int RGF_CENTERZ = 16;
+
+// Flags for A_Mushroom
+const int MSF_Standard = 0;
+const int MSF_Classic = 1;
+const int MSF_DontHurt = 2;
+
+// Flags for A_Explode
+const int XF_HURTSOURCE = 1;
+const int XF_NOTMISSILE = 4;
+
+// Flags for A_RadiusThrust
+const int RTF_AFFECTSOURCE = 1;
+const int RTF_NOIMPACTDAMAGE = 2;
+const int RTF_NOTMISSILE = 4;
+
+// Flags for A_Blast
+const int BF_USEAMMO = 1;
+const int BF_DONTWARN = 2;
+const int BF_AFFECTBOSSES = 4;
+const int BF_NOIMPACTDAMAGE = 8;
+
+// Flags for A_SeekerMissile
+const int SMF_LOOK = 1;
+const int SMF_PRECISE = 2;
+const int SMF_CURSPEED = 4;
+
+// Flags for A_CustomPunch
+const int CPF_USEAMMO = 1;
+const int CPF_DAGGER = 2;
+const int CPF_PULLIN = 4;
+const int CPF_NORANDOMPUFFZ = 8;
+
+// Flags for A_CustomMissile
+const int FPF_AIMATANGLE = 1;
+const int FPF_TRANSFERTRANSLATION = 2;
+
+// Flags for A_Teleport
+const int TF_TELEFRAG = 1;const int TF_RANDOMDECIDE = 2;
+
+// Flags for A_WolfAttack
+const int WAF_NORANDOM = 1;
+const int WAF_USEPUFF = 2;
+
+// Flags for A_RadiusGive
+enum
+{
+	RGF_GIVESELF	=   1,
+	RGF_PLAYERS		=   2,
+	RGF_MONSTERS	=   4,
+	RGF_OBJECTS		=   8,
+	RGF_VOODOO		=  16,
+	RGF_CORPSES		=  32,
+	RGF_NOTARGET	=  64,
+	RGF_NOTRACER	= 128,
+	RGF_NOMASTER	= 256,
+	RGF_CUBE		= 512,
+};
+
+// Activation flags
+enum
+{
+	THINGSPEC_Default = 0,
+	THINGSPEC_ThingActs = 1,
+	THINGSPEC_ThingTargets = 2,
+	THINGSPEC_TriggerTargets = 4,
+	THINGSPEC_MonsterTrigger = 8,
+	THINGSPEC_MissileTrigger = 16,
+	THINGSPEC_ClearSpecial = 32,
+	THINGSPEC_NoDeathSpecial = 64,
+	THINGSPEC_TriggerActs = 128,
+};
+// Shorter aliases for same
+const int AF_Default = 0;
+const int AF_ThingActs = 1;
+const int AF_ThingTargets = 2;
+const int AF_TriggerTargets = 4;
+const int AF_MonsterTrigger = 8;
+const int AF_MissileTrigger = 16;
+const int AF_ClearSpecial = 32;
+const int AF_NoDeathSpecial = 64;
+const int AF_TriggerActs = 128;
+
+// Flags for A_TakeInventory and A_TakeFromTarget
+const int TIF_NOTAKEINFINITE = 1;
+
+// constants for A_PlaySound
+enum
+{
+	CHAN_AUTO = 0,
+	CHAN_WEAPON = 1,
+	CHAN_VOICE = 2,
+	CHAN_ITEM = 3,
+	CHAN_BODY = 4,
+	CHAN_5 = 5,
+	CHAN_6 = 6,
+	CHAN_7 = 7,
+	
+	// modifier flags
+	CHAN_LISTENERZ = 8,
+	CHAN_MAYBE_LOCAL = 16,
+	CHAN_UI = 32,
+	CHAN_NOPAUSE = 64
+};
+
+// sound attenuation values
+const float ATTN_NONE = 0;
+const float ATTN_NORM = 1;
+const float ATTN_IDLE = 1.001;
+const float ATTN_STATIC = 3;
+
+// For SetPlayerProprty action special
+Const Int PROP_FROZEN = 0;
+Const Int PROP_NOTARGET = 1;
+Const Int PROP_INSTANTWEAPONSWITCH = 2;
+Const Int PROP_FLY = 3;
+Const Int PROP_TOTALLYFROZEN = 4;
+Const Int PROP_INVULNERABILITY  = 5; // (Deprecated)
+Const Int PROP_STRENGTH = 6; // (Deprecated)
+Const Int PROP_INVISIBILITY = 7; // (Deprecated)
+Const Int PROP_RADIATIONSUIT = 8; // (Deprecated)
+Const Int PROP_ALLMAP = 9; // (Deprecated)
+Const Int PROP_INFRARED = 10; // (Deprecated)
+Const Int PROP_WEAPONLEVEL2 = 11; // (Deprecated)
+Const Int PROP_FLIGHT = 12; // (Deprecated)
+Const Int PROP_SPEED = 15; // (Deprecated)
+Const Int PROP_BUDDHA = 16;
+
+// Line_SetBlocking
+Const Int BLOCKF_CREATURES = 1;
+Const Int BLOCKF_MONSTERS = 2;
+Const Int BLOCKF_PLAYERS = 4;
+Const Int BLOCKF_FLOATERS = 8;
+Const Int BLOCKF_PROJECTILES = 16;
+Const Int BLOCKF_EVERYTHING = 32;
+Const Int BLOCKF_RAILING = 64;
+Const Int BLOCKF_USE = 128;
+
+// Pointer constants, bitfield-enabled
+
+Const Int AAPTR_DEFAULT = 0;
+Const Int AAPTR_NULL = 0x1;
+Const Int AAPTR_TARGET = 0x2;
+Const Int AAPTR_MASTER = 0x4;
+Const Int AAPTR_TRACER = 0x8;
+
+Const Int AAPTR_PLAYER_GETTARGET = 0x10;
+Const Int AAPTR_PLAYER_GETCONVERSATION = 0x20;
+
+Const Int AAPTR_PLAYER1 = 0x40;
+Const Int AAPTR_PLAYER2 = 0x80;
+Const Int AAPTR_PLAYER3 = 0x100;
+Const Int AAPTR_PLAYER4 = 0x200;
+Const Int AAPTR_PLAYER5 = 0x400;
+Const Int AAPTR_PLAYER6 = 0x800;
+Const Int AAPTR_PLAYER7 = 0x1000;
+Const Int AAPTR_PLAYER8 = 0x2000;
+
+Const Int AAPTR_FRIENDPLAYER = 0x4000;
+Const Int AAPTR_LINETARGET = 0x8000;
+
+// Pointer operation flags
+
+Const Int PTROP_UNSAFETARGET = 1;
+Const Int PTROP_UNSAFEMASTER = 2;
+Const Int PTROP_NOSAFEGUARDS = PTROP_UNSAFETARGET|PTROP_UNSAFEMASTER;
+
+
+// Flags for A_Warp
+
+Const Int WARPF_ABSOLUTEOFFSET = 0x1;
+Const Int WARPF_ABSOLUTEANGLE = 0x2;
+Const Int WARPF_USECALLERANGLE = 0x4;
+Const Int WARPF_NOCHECKPOSITION = 0x8;
+Const Int WARPF_INTERPOLATE = 0x10;
+Const Int WARPF_WARPINTERPOLATION = 0x20;
+Const Int WARPF_COPYINTERPOLATION = 0x40;
+Const Int WARPF_STOP = 0x80;
+Const Int WARPF_TOFLOOR = 0x100;
+Const Int WARPF_TESTONLY = 0x200;
+Const Int WAPRF_ABSOLUTEPOSITION = 0x400;
+
+// flags for A_SetPitch/SetAngle
+const int SPF_FORCECLAMP = 1;
+const int SPF_INTERPOLATE = 2;
+
+
+// flags for A_CheckLOF
+
+enum
+{
+	CLOFF_NOAIM_VERT =			0x1,
+	CLOFF_NOAIM_HORZ =			0x2,
+
+	CLOFF_JUMPENEMY =			0x4,
+	CLOFF_JUMPFRIEND =			0x8,
+	CLOFF_JUMPOBJECT =			0x10,
+	CLOFF_JUMPNONHOSTILE =		0x20,
+
+	CLOFF_SKIPENEMY =			0x40,
+	CLOFF_SKIPFRIEND =			0x80,
+	CLOFF_SKIPOBJECT =			0x100,
+	CLOFF_SKIPNONHOSTILE =		0x200,
+
+	CLOFF_MUSTBESHOOTABLE =		0x400,
+
+	CLOFF_SKIPTARGET =			0x800,
+	CLOFF_ALLOWNULL =			0x1000,
+	CLOFF_CHECKPARTIAL =		0x2000,
+
+	CLOFF_MUSTBEGHOST =			0x4000,
+	CLOFF_IGNOREGHOST =			0x8000,
+	
+	CLOFF_MUSTBESOLID =			0x10000,
+	CLOFF_BEYONDTARGET =		0x20000,
+
+	CLOFF_FROMBASE =			0x40000,
+	CLOFF_MUL_HEIGHT =			0x80000,
+	CLOFF_MUL_WIDTH =			0x100000,
+
+	CLOFF_JUMP_ON_MISS =		0x200000,
+	CLOFF_AIM_VERT_NOOFFSET =	0x400000,
+
+	CLOFF_SKIPOBSTACLES = CLOFF_SKIPENEMY|CLOFF_SKIPFRIEND|CLOFF_SKIPOBJECT|CLOFF_SKIPNONHOSTILE,
+	CLOFF_NOAIM = CLOFF_NOAIM_VERT|CLOFF_NOAIM_HORZ
+};
+
+// Flags for A_Kill (Master/Target/Tracer/Children/Siblings) series
+
+const int KILS_FOILINVUL =		1;
+const int KILS_KILLMISSILES =	2;
+const int KILS_NOMONSTERS =		4;
+
+// Flags for A_Damage (Master/Target/Tracer/Children/Siblings/Self) series
+const int DMSS_FOILINVUL =		1;
+const int DMSS_AFFECTARMOR =	2;
+const int DMSS_KILL =			4;
+const int DMSS_NOFACTOR =		8;
+
+// Flags for A_AlertMonsters
+const int AMF_TARGETEMITTER = 1;
+const int AMF_TARGETNONPLAYER = 2;
+const int AMF_EMITFROMTARGET = 4;
+
+// Flags for A_Remove*
+enum
+{
+	RMVF_MISSILES =			1 << 0,
+	RMVF_NOMONSTERS =		1 << 1,
+	RMVF_MISC =				1 << 2,
+	RMVF_EVERYTHING =		1 << 3,
+};
+
+
+// This is only here to provide one global variable for testing.
+native int testglobalvar;
diff --git a/wadsrc/static/menudef.txt b/wadsrc/static/menudef.txt
index 6d313faf14..13565da7f2 100644
--- a/wadsrc/static/menudef.txt
+++ b/wadsrc/static/menudef.txt
@@ -458,6 +458,7 @@ OptionMenu "CustomizeControls"
 	Control 	"Run",					"+speed"
 	Control 	"Strafe",				"+strafe"
 	Control 	"Show Scoreboard",		"+showscores"
+	Control 	"Toggle Scoreboard",	"togglescoreboard"
 	StaticText 	""
 	StaticText 	"Chat", 1
 	Control 	"Say",					"messagemode"
@@ -1612,6 +1613,8 @@ OptionMenu NetworkOptions
 	StaticText "Local options", 1
 	Option "Movement prediction",		"cl_noprediction", "OffOn"
 	Option "Predict line actions",		"cl_predict_specials", "OnOff"
+	Slider "Prediction Lerp Scale",		"cl_predict_lerpscale", 0.0, 0.5, 0.05
+	Slider "Lerp Threshold",			"cl_predict_lerpthreshold", 0.1, 16.0, 0.1
 	StaticText " "
 	StaticText "Host options", 1
 	Option "Extra Tics",				"net_extratic", "ExtraTicMode"