diff --git a/src/d_main.cpp b/src/d_main.cpp
index bddac2704..7a36d0c86 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -780,7 +780,7 @@ void D_Display ()
 				viewwindowx + viewwidth, viewwindowy + viewheight);
 
 			// [ZZ] execute event hook that we just started the frame
-			E_RenderFrame();
+			//E_RenderFrame();
 			//
 			Renderer->RenderView(&players[consoleplayer]);
 
@@ -901,7 +901,7 @@ void D_Display ()
 		NetUpdate ();			// send out any new accumulation
 		// normal update
 		// draw ZScript UI stuff
-		E_RenderOverlay();
+		//E_RenderOverlay();
 		C_DrawConsole (hw2d);	// draw console
 		M_Drawer ();			// menu is drawn even on top of everything
 		FStat::PrintStat ();
diff --git a/src/d_player.h b/src/d_player.h
index 92f05c346..ce1c8093d 100644
--- a/src/d_player.h
+++ b/src/d_player.h
@@ -156,12 +156,12 @@ public:
 	double		ViewBob;
 
 	// Former class properties that were moved into the object to get rid of the meta class.
-	FName SoundClass;		// Sound class
-	FName Face;			// Doom status bar face (when used)
-	FName Portrait;
-	FName Slot[10];
-	FName InvulMode;
-	FName HealingRadiusType;
+	FNameNoInit SoundClass;		// Sound class
+	FNameNoInit Face;			// Doom status bar face (when used)
+	FNameNoInit Portrait;
+	FNameNoInit Slot[10];
+	FNameNoInit InvulMode;
+	FNameNoInit HealingRadiusType;
 	double HexenArmor[5];
 	BYTE ColorRangeStart;	// Skin color range
 	BYTE ColorRangeEnd;
diff --git a/src/dobjtype.cpp b/src/dobjtype.cpp
index 5d4ec59c9..211c73e82 100644
--- a/src/dobjtype.cpp
+++ b/src/dobjtype.cpp
@@ -1529,6 +1529,17 @@ bool PClassPointer::isCompatible(PType *type)
 	return (other != nullptr && other->ClassRestriction->IsDescendantOf(ClassRestriction));
 }
 
+//==========================================================================
+//
+// PClassPointer :: SetPointer
+//
+//==========================================================================
+
+void PClassPointer::SetPointer(void *base, unsigned offset, TArray<size_t> *special) const
+{
+	// Class pointers do not get added to FlatPointers because they are released from the GC.
+}
+
 //==========================================================================
 //
 // PClassPointer :: IsMatch
diff --git a/src/dobjtype.h b/src/dobjtype.h
index cc0a17da8..0151e6c11 100644
--- a/src/dobjtype.h
+++ b/src/dobjtype.h
@@ -401,6 +401,7 @@ public:
 
 	bool isCompatible(PType *type);
 
+	void SetPointer(void *base, unsigned offset, TArray<size_t> *special = NULL) const override;
 	virtual bool IsMatch(intptr_t id1, intptr_t id2) const;
 	virtual void GetTypeIDs(intptr_t &id1, intptr_t &id2) const;
 };
diff --git a/src/g_inventory/a_weapons.cpp b/src/g_inventory/a_weapons.cpp
index af180a4ea..fa9f63afa 100644
--- a/src/g_inventory/a_weapons.cpp
+++ b/src/g_inventory/a_weapons.cpp
@@ -230,7 +230,7 @@ bool AWeapon::CheckAmmo (int fireMode, bool autoSwitch, bool requireAmmo, int am
 	int enough, enoughmask;
 	int lAmmoUse1;
 
-	if ((dmflags & DF_INFINITE_AMMO) || (Owner->player->cheats & CF_INFINITEAMMO))
+	if ((dmflags & DF_INFINITE_AMMO) || (Owner->FindInventory (PClass::FindActor(NAME_PowerInfiniteAmmo), true) != nullptr))
 	{
 		return true;
 	}
@@ -311,7 +311,7 @@ DEFINE_ACTION_FUNCTION(AWeapon, CheckAmmo)
 
 bool AWeapon::DepleteAmmo (bool altFire, bool checkEnough, int ammouse)
 {
-	if (!((dmflags & DF_INFINITE_AMMO) || (Owner->player->cheats & CF_INFINITEAMMO)))
+	if (!((dmflags & DF_INFINITE_AMMO) || (Owner->FindInventory (PClass::FindActor(NAME_PowerInfiniteAmmo), true) != nullptr)))
 	{
 		if (checkEnough && !CheckAmmo (altFire ? AltFire : PrimaryFire, false, false, ammouse))
 		{
diff --git a/src/g_level.cpp b/src/g_level.cpp
index c34a80bb7..0842f3ec8 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -1365,7 +1365,7 @@ void G_FinishTravel ()
 		for (int i = 0; i < pawnsnum; i++)
 		{
 			// [ZZ] fire the enter hook.
-			E_PlayerEntered(pawns[i]->player - players, true);
+			E_PlayerEntered(int(pawns[i]->player - players), true);
 			//
 			FBehavior::StaticStartTypedScripts(SCRIPT_Return, pawns[i], true);
 		}
diff --git a/src/m_cheat.cpp b/src/m_cheat.cpp
index 75e765d80..382775fce 100644
--- a/src/m_cheat.cpp
+++ b/src/m_cheat.cpp
@@ -351,7 +351,7 @@ void cht_DoCheat (player_t *player, int cheat)
 
 				// player is now alive.
 				// fire E_PlayerRespawned and start the ACS SCRIPT_Respawn.
-				E_PlayerRespawned(player - players);
+				E_PlayerRespawned(int(player - players));
 				//
 				FBehavior::StaticStartTypedScripts(SCRIPT_Respawn, player->mo, true);
 
diff --git a/src/menu/menu.cpp b/src/menu/menu.cpp
index 9d8e5f4f3..a8dac6b54 100644
--- a/src/menu/menu.cpp
+++ b/src/menu/menu.cpp
@@ -270,6 +270,7 @@ bool DMenu::CallMenuEvent(int mkey, bool fromcontroller)
 
 void DMenu::Close ()
 {
+	if (DMenu::CurrentMenu == nullptr) return;	// double closing can happen in the save menu.
 	assert(DMenu::CurrentMenu == this);
 	DMenu::CurrentMenu = mParentMenu;
 	Destroy();
@@ -1283,7 +1284,7 @@ DMenuItemBase * CreateOptionMenuItemSubmenu(const char *label, FName cmd, int ce
 
 DMenuItemBase * CreateOptionMenuItemControl(const char *label, FName cmd, FKeyBindings *bindings)
 {
-	auto c = PClass::FindClass("OptionMenuItemControl");
+	auto c = PClass::FindClass("OptionMenuItemControlBase");
 	auto p = c->CreateNew();
 	VMValue params[] = { p, FString(label), cmd.GetIndex(), bindings };
 	auto f = dyn_cast<PFunction>(c->Symbols.FindSymbol("Init", false));
diff --git a/src/namedef.h b/src/namedef.h
index a010fbb8a..ebd9f3e8e 100644
--- a/src/namedef.h
+++ b/src/namedef.h
@@ -203,6 +203,8 @@ xx(CallTryPickup)
 xx(QuestItem25)
 xx(QuestItem28)
 xx(QuestItem29)
+xx(PowerDoubleFiringSpeed)
+xx(PowerInfiniteAmmo)
 
 xx(AcolyteBlue)
 xx(SpectralLightningV1)
diff --git a/src/p_3dfloors.cpp b/src/p_3dfloors.cpp
index fa7b66d65..b699fadbd 100644
--- a/src/p_3dfloors.cpp
+++ b/src/p_3dfloors.cpp
@@ -773,7 +773,7 @@ void P_LineOpening_XFloors (FLineOpening &open, AActor * thing, const line_t *li
 			int highestfloorterrain = -1;
 			FTextureID lowestceilingpic;
 			sector_t *lowestceilingsec = NULL, *highestfloorsec = NULL;
-			secplane_t *highestfloorplanes[2] = { NULL, NULL };
+			secplane_t *highestfloorplanes[2] = { &open.frontfloorplane, &open.backfloorplane };
 			
 			highestfloorpic.SetInvalid();
 			lowestceilingpic.SetInvalid();
@@ -800,13 +800,19 @@ void P_LineOpening_XFloors (FLineOpening &open, AActor * thing, const line_t *li
 						lowestceilingsec = j == 0 ? linedef->frontsector : linedef->backsector;
 					}
 					
-					if(ff_top > highestfloor && delta1 <= delta2 && (!restrict || thing->Z() >= ff_top))
+					if(delta1 <= delta2 && (!restrict || thing->Z() >= ff_top))
 					{
-						highestfloor = ff_top;
-						highestfloorpic = *rover->top.texture;
-						highestfloorterrain = rover->model->GetTerrain(rover->top.isceiling);
-						highestfloorsec = j == 0 ? linedef->frontsector : linedef->backsector;
-						highestfloorplanes[j] = rover->top.plane;
+						if (ff_top > highestfloor)
+						{
+							highestfloor = ff_top;
+							highestfloorpic = *rover->top.texture;
+							highestfloorterrain = rover->model->GetTerrain(rover->top.isceiling);
+							highestfloorsec = j == 0 ? linedef->frontsector : linedef->backsector;
+						}
+						if (ff_top > highestfloorplanes[j]->ZatPoint(x, y))
+						{
+							highestfloorplanes[j] = rover->top.plane;
+						}
 					}
 					if(ff_top > lowestfloor[j] && ff_top <= thing->Z() + thing->MaxStepHeight) lowestfloor[j] = ff_top;
 				}
@@ -818,18 +824,18 @@ void P_LineOpening_XFloors (FLineOpening &open, AActor * thing, const line_t *li
 				open.floorpic = highestfloorpic;
 				open.floorterrain = highestfloorterrain;
 				open.bottomsec = highestfloorsec;
-				if (highestfloorplanes[0])
-				{
-					open.frontfloorplane = *highestfloorplanes[0];
-					if (open.frontfloorplane.fC() < 0) open.frontfloorplane.FlipVert();
-				}
-				if (highestfloorplanes[1])
-				{
-					open.backfloorplane = *highestfloorplanes[1];
-					if (open.backfloorplane.fC() < 0) open.backfloorplane.FlipVert();
-				}
 			}
-			
+			if (highestfloorplanes[0] != &open.frontfloorplane)
+			{
+				open.frontfloorplane = *highestfloorplanes[0];
+				if (open.frontfloorplane.fC() < 0) open.frontfloorplane.FlipVert();
+			}
+			if (highestfloorplanes[1] != &open.backfloorplane)
+			{
+				open.backfloorplane = *highestfloorplanes[1];
+				if (open.backfloorplane.fC() < 0) open.backfloorplane.FlipVert();
+			}
+
 			if(lowestceiling < open.top) 
 			{
 				open.top = lowestceiling;
diff --git a/src/p_actionfunctions.cpp b/src/p_actionfunctions.cpp
index 40629bfcb..15e82a56c 100644
--- a/src/p_actionfunctions.cpp
+++ b/src/p_actionfunctions.cpp
@@ -1410,26 +1410,6 @@ DEFINE_ACTION_FUNCTION(AActor, A_RadiusDamageSelf)
 	return 0;
 }
 
-//==========================================================================
-//
-// Execute a line special / script
-//
-//==========================================================================
-DEFINE_ACTION_FUNCTION(AActor, A_CallSpecial)
-{
-	PARAM_SELF_PROLOGUE(AActor);
-	PARAM_INT		(special);
-	PARAM_INT_DEF	(arg1);
-	PARAM_INT_DEF	(arg2);
-	PARAM_INT_DEF	(arg3);
-	PARAM_INT_DEF	(arg4);
-	PARAM_INT_DEF	(arg5);
-
-	bool res = !!P_ExecuteSpecial(special, NULL, self, false, arg1, arg2, arg3, arg4, arg5);
-
-	ACTION_RETURN_BOOL(res);
-}
-
 //==========================================================================
 //
 // The ultimate code pointer: Fully customizable missiles!
diff --git a/src/p_interaction.cpp b/src/p_interaction.cpp
index 043c0a783..47789c0cb 100644
--- a/src/p_interaction.cpp
+++ b/src/p_interaction.cpp
@@ -612,7 +612,7 @@ void AActor::Die (AActor *source, AActor *inflictor, int dmgflags)
 		ClientObituary (this, inflictor, source, dmgflags);
 
 		// [ZZ] fire player death hook
-		E_PlayerDied(player - players);
+		E_PlayerDied(int(player - players));
 
 		// Death script execution, care of Skull Tag
 		FBehavior::StaticStartTypedScripts (SCRIPT_Death, this, true);
diff --git a/src/p_lnspec.cpp b/src/p_lnspec.cpp
index 5375085dd..6f44cedcd 100644
--- a/src/p_lnspec.cpp
+++ b/src/p_lnspec.cpp
@@ -2841,7 +2841,7 @@ FUNC(LS_SetPlayerProperty)
 	// Add or remove a power
 	if (arg2 >= PROP_INVULNERABILITY && arg2 <= PROP_SPEED)
 	{
-		static ENamedName powers[11] =
+		static ENamedName powers[13] =
 		{
 			NAME_PowerInvulnerable,
 			NAME_PowerStrength,
@@ -2853,7 +2853,9 @@ FUNC(LS_SetPlayerProperty)
 			NAME_PowerFlight,
 			NAME_None,
 			NAME_None,
-			NAME_PowerSpeed
+			NAME_PowerSpeed,
+			NAME_PowerInfiniteAmmo,
+			NAME_PowerDoubleFiringSpeed
 		};
 		int power = arg2 - PROP_INVULNERABILITY;
 
@@ -3715,3 +3717,27 @@ int P_ExecuteSpecial(int			num,
 	}
 	return 0;
 }
+
+//==========================================================================
+//
+// Execute a line special / script
+//
+//==========================================================================
+DEFINE_ACTION_FUNCTION(FLevelLocals, ExecuteSpecial)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FLevelLocals);
+	PARAM_INT(special);
+	PARAM_OBJECT(activator, AActor);
+	PARAM_POINTER(linedef, line_t);
+	PARAM_BOOL(lineside);
+	PARAM_INT_DEF(arg1);
+	PARAM_INT_DEF(arg2);
+	PARAM_INT_DEF(arg3);
+	PARAM_INT_DEF(arg4);
+	PARAM_INT_DEF(arg5);
+
+	bool res = !!P_ExecuteSpecial(special, linedef, activator, lineside, arg1, arg2, arg3, arg4, arg5);
+
+	ACTION_RETURN_BOOL(res);
+}
+
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 3d7098d70..c1e68f3b3 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -144,7 +144,6 @@ IMPLEMENT_POINTERS_START(AActor)
 	IMPLEMENT_POINTER(LastHeard)
 	IMPLEMENT_POINTER(master)
 	IMPLEMENT_POINTER(Poisoner)
-	IMPLEMENT_POINTER(DamageFunc)
 	IMPLEMENT_POINTER(alternative)
 IMPLEMENT_POINTERS_END
 
@@ -5514,7 +5513,7 @@ APlayerPawn *P_SpawnPlayer (FPlayerStart *mthing, int playernum, int flags)
 		{
 			// [ZZ] fire non-hub ENTER event
 			//      level.time is a hack to make sure that we don't call it on dummy player initialization during hub return.
-			if (!level.time) E_PlayerEntered(p - players, false);
+			if (!level.time) E_PlayerEntered(int(p - players), false);
 			FBehavior::StaticStartTypedScripts (SCRIPT_Enter, p->mo, true);
 		}
 		else if (state == PST_REBORN)
diff --git a/src/p_pspr.cpp b/src/p_pspr.cpp
index bf6c79a82..8b8e93f6a 100644
--- a/src/p_pspr.cpp
+++ b/src/p_pspr.cpp
@@ -1381,7 +1381,7 @@ void DPSprite::Tick()
 			Tics--;
 
 			// [BC] Apply double firing speed.
-			if ((Flags & PSPF_POWDOUBLE) && Tics && (Owner->cheats & CF_DOUBLEFIRINGSPEED))
+			if ((Flags & PSPF_POWDOUBLE) && Tics && (Owner->mo->FindInventory (PClass::FindActor(NAME_PowerDoubleFiringSpeed), true)))
 				Tics--;
 
 			if (!Tics)
diff --git a/src/p_saveg.cpp b/src/p_saveg.cpp
index 8f465e081..a3208598d 100644
--- a/src/p_saveg.cpp
+++ b/src/p_saveg.cpp
@@ -832,7 +832,10 @@ void CopyPlayer(player_t *dst, player_t *src, const char *name)
 	else
 	{
 		dst->userinfo.TransferFrom(uibackup);
+		// The player class must come from the save, so that the menu reflects the currently playing one.
+		dst->userinfo.PlayerClassChanged(src->mo->GetClass()->DisplayName); 
 	}
+
 	// Validate the skin
 	dst->userinfo.SkinNumChanged(R_FindSkin(skins[dst->userinfo.GetSkin()].name, dst->CurrentPlayerClass));
 
diff --git a/src/p_trace.cpp b/src/p_trace.cpp
index 3597535e5..818372e74 100644
--- a/src/p_trace.cpp
+++ b/src/p_trace.cpp
@@ -41,6 +41,7 @@
 #include "r_defs.h"
 #include "p_spec.h"
 #include "g_levellocals.h"
+#include "p_terrain.h"
 
 //==========================================================================
 //
@@ -135,6 +136,13 @@ static void GetPortalTransition(DVector3 &pos, sector_t *&sec)
 	}
 }
 
+static bool isLiquid(F3DFloor *ff)
+{
+	if (ff->flags & FF_SWIMMABLE) return true;
+	auto terrain = ff->model->GetTerrain(ff->flags & FF_INVERTPLANES ? sector_t::floor : sector_t::ceiling);
+	return Terrains[terrain].IsLiquid && Terrains[terrain].Splash != -1;
+}
+
 //==========================================================================
 //
 // Trace entry point
@@ -300,9 +308,9 @@ void FTraceInfo::Setup3DFloors()
 			if (!(rover->flags&FF_EXISTS))
 				continue;
 
-			if (rover->flags&FF_SWIMMABLE && Results->Crossed3DWater == NULL)
+			if (Results->Crossed3DWater == NULL)
 			{
-				if (Check3DFloorPlane(rover, false))
+				if (Check3DFloorPlane(rover, false) && isLiquid(rover))
 				{
 					// only consider if the plane is above the actual floor.
 					if (rover->top.plane->ZatPoint(Results->HitPos) > bf)
@@ -767,7 +775,7 @@ bool FTraceInfo::TraceTraverse (int ptflags)
 		{
 			for (auto rover : CurSector->e->XFloor.ffloors)
 			{
-				if ((rover->flags & FF_EXISTS) && (rover->flags&FF_SWIMMABLE))
+				if ((rover->flags & FF_EXISTS) && isLiquid(rover))
 				{
 					if (Check3DFloorPlane(rover, false))
 					{
diff --git a/src/p_udmf.cpp b/src/p_udmf.cpp
index a13c24e63..fc71160ae 100644
--- a/src/p_udmf.cpp
+++ b/src/p_udmf.cpp
@@ -1854,7 +1854,7 @@ public:
 			intptr_t v1i = intptr_t(ParsedLines[i].v1);
 			intptr_t v2i = intptr_t(ParsedLines[i].v2);
 
-			if (v1i >= level.vertexes.Size() || v2i >= level.vertexes.Size() || v1i < 0 || v2i < 0)
+			if ((unsigned)v1i >= level.vertexes.Size() || (unsigned)v2i >= level.vertexes.Size())
 			{
 				I_Error ("Line %d has invalid vertices: %zd and/or %zd.\nThe map only contains %u vertices.", i+skipped, v1i, v2i, level.vertexes.Size());
 			}
diff --git a/src/p_user.cpp b/src/p_user.cpp
index d5e8afdaf..dbdf08002 100644
--- a/src/p_user.cpp
+++ b/src/p_user.cpp
@@ -1233,8 +1233,6 @@ const char *APlayerPawn::GetSoundClass() const
 		return skins[player->userinfo.GetSkin()].name;
 	}
 
-	// [GRB]
-	auto pclass = GetClass();
 	return SoundClass != NAME_None? SoundClass.GetChars() : "player";
 }
 
diff --git a/wadsrc/static/zscript/actor.txt b/wadsrc/static/zscript/actor.txt
index 5e2454ed2..0666fce8b 100644
--- a/wadsrc/static/zscript/actor.txt
+++ b/wadsrc/static/zscript/actor.txt
@@ -737,7 +737,11 @@ class Actor : Thinker native
 	native void A_VileChase();
 	native void A_BossDeath();
 	native void A_Detonate();
-	native bool A_CallSpecial(int special, int arg1=0, int arg2=0, int arg3=0, int arg4=0, int arg5=0);
+	bool A_CallSpecial(int special, int arg1=0, int arg2=0, int arg3=0, int arg4=0, int arg5=0)
+	{
+		return Level.ExecuteSpecial(special, self, null, false, arg1, arg2, arg3, arg4, arg5);
+	}
+
 
 	native void A_ActiveSound();
 
diff --git a/wadsrc/static/zscript/base.txt b/wadsrc/static/zscript/base.txt
index bffee91f0..7b872f472 100644
--- a/wadsrc/static/zscript/base.txt
+++ b/wadsrc/static/zscript/base.txt
@@ -469,6 +469,7 @@ struct LevelLocals native
 	native String GetUDMFString(int type, int index, Name key);
 	native int GetUDMFInt(int type, int index, Name key);
 	native double GetUDMFFloat(int type, int index, Name key);
+	native bool ExecuteSpecial(int special, Actor activator, line linedef, bool lineside, int arg1 = 0, int arg2 = 0, int arg3 = 0, int arg4 = 0, int arg5 = 0);
 
 }
 
diff --git a/wadsrc/static/zscript/inventory/powerups.txt b/wadsrc/static/zscript/inventory/powerups.txt
index d355a5e14..828113ac8 100644
--- a/wadsrc/static/zscript/inventory/powerups.txt
+++ b/wadsrc/static/zscript/inventory/powerups.txt
@@ -1767,7 +1767,7 @@ class PowerProtection : Powerup
 	{
 		if (passive && damage > 0)
 		{
-			newdamage = max(1, ApplyDamageFactors(GetClass(), damageType, damage, damage / 4));
+			newdamage = max(0, ApplyDamageFactors(GetClass(), damageType, damage, damage / 4));
 			if (Owner != null && newdamage < damage) Owner.A_PlaySound(ActiveSound, CHAN_AUTO, 1.0, false, ATTN_NONE);
 		}
 	}
diff --git a/wadsrc/static/zscript/shared/movingcamera.txt b/wadsrc/static/zscript/shared/movingcamera.txt
index 15fdd0836..c6af13b42 100644
--- a/wadsrc/static/zscript/shared/movingcamera.txt
+++ b/wadsrc/static/zscript/shared/movingcamera.txt
@@ -311,7 +311,7 @@ class PathFollower : Actor
 
 		while ( (spec = InterpolationSpecial(iterator.Next ())) )
 		{
-			A_CallSpecial(spec.special, spec.args[0], spec.args[1], spec.args[2], spec.args[3], spec.args[4]);
+			Level.ExecuteSpecial(spec.special, null, null, false, spec.args[0], spec.args[1], spec.args[2], spec.args[3], spec.args[4]);
 		}
 	}