diff --git a/src/am_map.cpp b/src/am_map.cpp
index 99fda3bd6..8fb46ed6b 100644
--- a/src/am_map.cpp
+++ b/src/am_map.cpp
@@ -473,6 +473,11 @@ static AMColorset AMMod;
 static AMColorset AMModOverlay;
 
 
+void AM_ClearColorsets()
+{
+	AMModOverlay.defined = false;
+	AMMod.defined = false;
+}
 //=============================================================================
 //
 //
diff --git a/src/am_map.h b/src/am_map.h
index dadacde55..fd9079c1e 100644
--- a/src/am_map.h
+++ b/src/am_map.h
@@ -27,6 +27,7 @@ class FSerializer;
 
 
 void AM_StaticInit();
+void AM_ClearColorsets();	// reset data for a restart.
 
 // Called by main loop.
 bool AM_Responder (event_t* ev, bool last);
diff --git a/src/d_main.cpp b/src/d_main.cpp
index bffb4136d..7cc40cc05 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -2598,44 +2598,48 @@ void D_DoomMain (void)
 				G_DeferedPlayDemo (v);
 				D_DoomLoop ();	// never returns
 			}
-
-			v = Args->CheckValue ("-timedemo");
-			if (v)
+			else
 			{
-				G_TimeDemo (v);
-				D_DoomLoop ();	// never returns
-			}
-
-			if (gameaction != ga_loadgame && gameaction != ga_loadgamehidecon)
-			{
-				if (autostart || netgame)
+				v = Args->CheckValue("-timedemo");
+				if (v)
 				{
-					// Do not do any screenwipes when autostarting a game.
-					if (!Args->CheckParm("-warpwipe"))
-					{
-						NoWipe = TICRATE;
-					}
-					CheckWarpTransMap (startmap, true);
-					if (demorecording)
-						G_BeginRecording (startmap);
-					G_InitNew (startmap, false);
-					if (StoredWarp.IsNotEmpty())
-					{
-						AddCommandString(StoredWarp.LockBuffer());
-						StoredWarp = NULL;
-					}
+					G_TimeDemo(v);
+					D_DoomLoop();	// never returns
 				}
 				else
 				{
-					D_StartTitle ();				// start up intro loop
+					if (gameaction != ga_loadgame && gameaction != ga_loadgamehidecon)
+					{
+						if (autostart || netgame)
+						{
+							// Do not do any screenwipes when autostarting a game.
+							if (!Args->CheckParm("-warpwipe"))
+							{
+								NoWipe = TICRATE;
+							}
+							CheckWarpTransMap(startmap, true);
+							if (demorecording)
+								G_BeginRecording(startmap);
+							G_InitNew(startmap, false);
+							if (StoredWarp.IsNotEmpty())
+							{
+								AddCommandString(StoredWarp.LockBuffer());
+								StoredWarp = NULL;
+							}
+						}
+						else
+						{
+							D_StartTitle();				// start up intro loop
+						}
+					}
+					else if (demorecording)
+					{
+						G_BeginRecording(NULL);
+					}
+
+					atterm(D_QuitNetGame);		// killough
 				}
 			}
-			else if (demorecording)
-			{
-				G_BeginRecording (NULL);
-			}
-						
-			atterm (D_QuitNetGame);		// killough
 		}
 		else
 		{
@@ -2649,7 +2653,7 @@ void D_DoomMain (void)
 		}
 
 		D_DoomLoop ();		// this only returns if a 'restart' CCMD is given.
-
+maxberestart:
 		// 
 		// Clean up after a restart
 		//
@@ -2660,6 +2664,7 @@ void D_DoomMain (void)
 
 		M_ClearMenus();					// close menu if open
 		F_EndFinale();					// If an intermission is active, end it now
+		AM_ClearColorsets();
 
 		// clean up game state
 		ST_Clear();
diff --git a/src/p_slopes.cpp b/src/p_slopes.cpp
index 66b3d0747..7413922e2 100644
--- a/src/p_slopes.cpp
+++ b/src/p_slopes.cpp
@@ -178,8 +178,8 @@ void P_SetSlope (secplane_t *plane, bool setCeil, int xyangi, int zangi, const D
 	if (ib_compatflags & BCOMPATF_SETSLOPEOVERFLOW)
 	{
 		// We have to consider an integer multiplication overflow here.
-		norm[0] = FixedToFloat(FloatToFixed(zang.Cos()) * FloatToFixed(xyang.Cos()));
-		norm[1] = FixedToFloat(FloatToFixed(zang.Cos()) * FloatToFixed(xyang.Sin()));
+		norm[0] = FixedToFloat(FloatToFixed(zang.Cos()) * FloatToFixed(xyang.Cos())) / 65536.;
+		norm[1] = FixedToFloat(FloatToFixed(zang.Cos()) * FloatToFixed(xyang.Sin())) / 65536.;
 	}
 	else
 	{
diff --git a/src/po_man.cpp b/src/po_man.cpp
index fafa227ee..15c8d5a52 100644
--- a/src/po_man.cpp
+++ b/src/po_man.cpp
@@ -1775,7 +1775,14 @@ void PO_Init (void)
 			}
 		}
 	}
-
+	// clear all polyobj specials so that they do not obstruct using other lines.
+	for (int i = 0; i < numlines; i++)
+	{
+		if (lines[i].special == Polyobj_ExplicitLine || lines[i].special == Polyobj_StartLine)
+		{
+			lines[i].special = 0;
+		}
+	}
 }
 
 //==========================================================================
diff --git a/wadsrc/static/compatibility.txt b/wadsrc/static/compatibility.txt
index d964cbf75..73a4f5af2 100644
--- a/wadsrc/static/compatibility.txt
+++ b/wadsrc/static/compatibility.txt
@@ -27,6 +27,7 @@
 	setwallyscale 717 front bot 1.090909
 
 	setslopeoverflow
+	polyobj
 }
 
 B2D8DA03489D1C67F60DC87FBC4EA338 // map01 - Massmouth 2