diff --git a/source/core/maphack.cpp b/source/core/maphack.cpp
index eb0158126..d9d0ddb3c 100644
--- a/source/core/maphack.cpp
+++ b/source/core/maphack.cpp
@@ -163,107 +163,6 @@ static int32_t LoadMapHack(const char *filename, SpawnSpriteDef& sprites)
 				}
 			}
 		}
-		else if (sc.Compare("picnum"))
-		{
-			if (sc.CheckNumber())
-			{
-				if (currentwall != -1 && validateWall())
-				{
-					wall[currentwall].picnum = sc.Number;
-				}
-				else if (currentsprite != -1 && validateSprite())
-				{
-					sprites.sprites[currentsprite].picnum = sc.Number;
-				}
-			}
-		}
-		else if (sc.Compare("overpicnum"))
-		{
-			if (sc.CheckNumber() && validateWall())
-			{
-				wall[currentwall].overpicnum = sc.Number;
-			}
-		}
-		else if (sc.Compare("overpicnum"))
-		{
-			if (sc.CheckNumber() && validateWall())
-			{
-				wall[currentwall].overpicnum = sc.Number;
-			}
-		}
-		else if (sc.Compare("split"))
-		{
-			int start = -1, end = -1;
-			if (sc.CheckNumber()) start = sc.Number;
-			if (sc.CheckNumber()) end = sc.Number;
-			if (end >= 0 && validateSector())
-			{
-				hw_SetSplitSector(currentsector, start, end);
-			}
-		}
-		else if (sc.Compare("dontclip"))
-		{
-			sector[currentsector].exflags |= SECTOREX_DONTCLIP;
-		}
-		else if (sc.Compare("clearflags"))
-		{
-			if (currentsector != -1 && validateSector())
-			{
-				sc.GetString();
-				if (sc.Compare("floor") && sc.CheckNumber())
-				{
-					sector[currentsector].floorstat &= ESectorFlags::FromInt(~sc.Number);
-				}
-				else if (sc.Compare("ceiling") && sc.CheckNumber())
-				{
-					sector[currentsector].ceilingstat &= ESectorFlags::FromInt(~sc.Number);
-				}
-				else sc.ScriptError("Bad token %s", sc.String);
-			}
-			else if (sc.CheckNumber())
-			{
-				if (currentwall != -1 && validateWall())
-				{
-					wall[currentwall].cstat &= EWallFlags::FromInt(~sc.Number);
-				}
-				else if (currentsprite != -1 && validateSprite())
-				{
-					sprites.sprites[currentsprite].cstat &= ESpriteFlags::FromInt(~sc.Number);
-				}
-			}
-		}
-		else if (sc.Compare("setflags"))
-		{
-			if (sc.CheckNumber())
-			{
-				if (currentwall != -1 && validateWall())
-				{
-					wall[currentwall].cstat |= EWallFlags::FromInt(sc.Number);
-				}
-				else if (currentsprite != -1 && validateSprite())
-				{
-					sprites.sprites[currentsprite].cstat |= ESpriteFlags::FromInt(sc.Number);
-				}
-			}
-		}
-		else if (sc.Compare("lotag"))
-		{
-			if (sc.CheckNumber())
-			{
-				if (currentwall != -1 && validateWall())
-				{
-					wall[currentwall].lotag = sc.Number;
-				}
-				else if (currentsprite != -1 && validateSprite())
-				{
-					sprites.sprites[currentsprite].lotag = sc.Number;
-				}
-			}
-		}
-		else if (sc.Compare("sw_serp_continue")) // This is a hack for SW's Last Warrior mod to continue from L4 to L5.
-		{
-			if (currentLevel) currentLevel->gameflags |= LEVEL_SW_DEATHEXIT_SERPENT_NEXT;
-		}
 
 		else if (sc.Compare("angleoff") || sc.Compare("angoff"))
 		{
@@ -383,8 +282,6 @@ static int32_t LoadMapHack(const char *filename, SpawnSpriteDef& sprites)
 
 void loadMapHack(const char* filename, const uint8_t* md4, SpawnSpriteDef& sprites)
 {
-	hw_ClearSplitSector();
-
 	FString internal = "engine/compatibility/";
 	for (int j = 0; j < 16; ++j)
 	{
diff --git a/source/core/maploader.cpp b/source/core/maploader.cpp
index 298f08af2..66e639f7d 100644
--- a/source/core/maploader.cpp
+++ b/source/core/maploader.cpp
@@ -543,6 +543,7 @@ void loadMap(const char* filename, int flags, DVector3* pos, int16_t* ang, secto
 	auto buffer = fr.Read();
 	uint8_t md4[16];
 	md4once(buffer.Data(), buffer.Size(), md4);
+	PostProcessLevel(md4, filename, sprites);
 	loadMapHack(filename, md4, sprites);
 	setWallSectors();
 	hw_CreateSections();
diff --git a/source/core/maptypes.h b/source/core/maptypes.h
index 4b848490b..c50836d6b 100644
--- a/source/core/maptypes.h
+++ b/source/core/maptypes.h
@@ -698,6 +698,7 @@ TArray<walltype> loadMapWalls(const char* filename);
 void loadMapBackup(const char* filename);
 void loadMapHack(const char* filename, const uint8_t*, SpawnSpriteDef& sprites);
 void validateStartSector(const char* filename, const DVector3& pos, sectortype** cursectnum, unsigned numsectors, bool noabort = false);
+void PostProcessLevel(const uint8_t* checksum, const FString& mapname, SpawnSpriteDef& sprites);
 
 // should only be used to read angles from map-loaded data (for proper documentation)
 constexpr DAngle mapangle(int mapang)
diff --git a/source/core/postprocessor.cpp b/source/core/postprocessor.cpp
index 7a48052e7..2230a7beb 100644
--- a/source/core/postprocessor.cpp
+++ b/source/core/postprocessor.cpp
@@ -37,6 +37,9 @@
 #include "vm.h"
 #include "printf.h"
 #include "types.h"
+#include "maptypes.h"
+#include "hw_sections.h"
+#include "mapinfo.h"
 
 //==========================================================================
 //
@@ -48,13 +51,21 @@ class DLevelPostProcessor : public DObject
 {
 	DECLARE_ABSTRACT_CLASS(DLevelPostProcessor, DObject)
 public:
+	SpawnSpriteDef* sprites;
 };
 
 IMPLEMENT_CLASS(DLevelPostProcessor, true, false);
 
-void PostProcessLevel(FName checksum, const FString& mapname)
+void PostProcessLevel(const uint8_t* md4, const FString& mapname, SpawnSpriteDef& sprites)
 {
+	hw_ClearSplitSector();
 	auto lc = Create<DLevelPostProcessor>();
+	lc->sprites = &sprites;
+
+	char md4string[33];
+	for (int i = 0; i < 16; i++) mysnprintf(md4string + 2 * i, 3, "%02x", md4[i]);
+	FName checksum(md4string, true);
+	if (checksum == NAME_None) return;	// we do not have anything so save the work.
 
 	for(auto cls : PClass::AllClasses)
 	{
@@ -83,21 +94,47 @@ void PostProcessLevel(FName checksum, const FString& mapname)
 DEFINE_ACTION_FUNCTION(DLevelPostProcessor, SetSpriteLotag)
 {
 	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
-	PARAM_INT(sprite);
+	PARAM_UINT(sprite);
 	PARAM_INT(lotag);
-	
-	// todo
+	if (sprite < self->sprites->sprites.Size())
+		self->sprites->sprites[sprite].lotag = lotag;
+
 	return 0;
 }
 
 DEFINE_ACTION_FUNCTION(DLevelPostProcessor, ChangeSpriteFlags)
 {
 	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
-	PARAM_INT(sprite);
+	PARAM_UINT(sprite);
 	PARAM_INT(clearmask);
-	PARAM_INT(setflag);
+	PARAM_INT(setmask);
+
+	if (sprite < self->sprites->sprites.Size())
+		self->sprites->sprites[sprite].cstat = (self->sprites->sprites[sprite].cstat & ~ESpriteFlags::FromInt(clearmask)) | ESpriteFlags::FromInt(setmask);
 
-	// todo
 	return 0;
 }
 
+DEFINE_ACTION_FUNCTION(DLevelPostProcessor, SplitSector)
+{
+	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
+	PARAM_UINT(sectornum);
+	PARAM_INT(firstwall);
+	PARAM_INT(secondwall);
+
+	if (sectornum < sector.Size())
+	{
+		if (firstwall >= sector[sectornum].wallptr && firstwall < sector[sectornum].wallptr + sector[sectornum].wallnum &&
+			secondwall >= sector[sectornum].wallptr && secondwall < sector[sectornum].wallptr + sector[sectornum].wallnum)
+
+			hw_SetSplitSector(sectornum, firstwall, secondwall);
+	}
+	return 0;
+}
+
+DEFINE_ACTION_FUNCTION(DLevelPostProcessor, sw_serp_continue)
+{
+	PARAM_SELF_PROLOGUE(DLevelPostProcessor);
+	currentLevel->gameflags |= LEVEL_SW_DEATHEXIT_SERPENT_NEXT;
+	return 0;
+}
diff --git a/source/core/thingdef_data.cpp b/source/core/thingdef_data.cpp
index 62282497d..da391588f 100644
--- a/source/core/thingdef_data.cpp
+++ b/source/core/thingdef_data.cpp
@@ -293,7 +293,7 @@ void InitThingdef()
 	//secplanestruct->Size = sizeof(secplane_t);
 	//secplanestruct->Align = alignof(secplane_t);
 
-	auto sectorstruct = NewStruct("Sector", nullptr, true);
+	auto sectorstruct = NewStruct("sectortype", nullptr, true);
 	sectorstruct->Size = sizeof(sectortype);
 	sectorstruct->Align = alignof(sectortype);
 	NewPointer(sectorstruct, false)->InstallHandlers(
@@ -308,7 +308,7 @@ void InitThingdef()
 		}
 	);
 
-	auto linestruct = NewStruct("Wall", nullptr, true);
+	auto linestruct = NewStruct("walltype", nullptr, true);
 	linestruct->Size = sizeof(walltype);
 	linestruct->Align = alignof(walltype);
 	NewPointer(linestruct, false)->InstallHandlers(
diff --git a/source/core/vmexports.cpp b/source/core/vmexports.cpp
index 98b814c11..2cc9b5133 100644
--- a/source/core/vmexports.cpp
+++ b/source/core/vmexports.cpp
@@ -35,6 +35,7 @@
 
 #include "maptypes.h"
 #include "vm.h"
+#include "gamefuncs.h"
 
 //=============================================================================
 //
@@ -496,6 +497,21 @@ DEFINE_ACTION_FUNCTION_NATIVE(_walltype, move, wall_move)
 	return 0;
 }
 
+void wall_dragpoint(walltype* wal, double x, double y)
+{
+	if (!wal) ThrowAbortException(X_READ_NIL, nullptr);
+	dragpoint(wal, DVector2(x, y));
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(_walltype, dragpoint, wall_dragpoint)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(walltype);
+	PARAM_FLOAT(x);
+	PARAM_FLOAT(y);
+	wall_dragpoint(self, x, y);
+	return 0;
+}
+
 int wall_twosided(walltype* wal)
 {
 	if (!wal) ThrowAbortException(X_READ_NIL, nullptr);
diff --git a/source/games/blood/src/db.cpp b/source/games/blood/src/db.cpp
index 49b5064e4..68e921aa8 100644
--- a/source/games/blood/src/db.cpp
+++ b/source/games/blood/src/db.cpp
@@ -593,6 +593,7 @@ void dbLoadMap(const char* pPath, DVector3& pos, short* pAngle, sectortype** cur
 	auto buffer = fr.Read();
 	uint8_t md4[16];
 	md4once(buffer.Data(), buffer.Size(), md4);
+	PostProcessLevel(md4, mapname, sprites);
 	loadMapHack(mapname, md4, sprites);
 
 	if (CalcCRC32(buffer.Data(), buffer.Size() - 4) != nCRC)
diff --git a/source/games/duke/src/premap_r.cpp b/source/games/duke/src/premap_r.cpp
index 539087c68..4daf49134 100644
--- a/source/games/duke/src/premap_r.cpp
+++ b/source/games/duke/src/premap_r.cpp
@@ -421,11 +421,6 @@ void prelevel_r(int g, TArray<DDukeActor*>& actors)
 	prelevel_common(g);
 	p = &ps[screenpeek];
 
-	if (currentLevel->levelNumber == 1001 && wall.Size() > 4687 && wall[4592].pos.X == 1612 && wall[4592].pos.Y == -2714) // fix sector overlap in E1L1 Taylor Town
-	{
-		dragpoint(&wall[4592], { 1615., -2715. });
-	}
-
 	if (currentLevel->gameflags & LEVEL_RR_CLEARMOONSHINE)
 		ps[myconnectindex].steroids_amount = 0;
 
diff --git a/wadsrc/static/engine/compatibility/24c7b1434070dbe01fa83c6a48926ed9.mhk b/wadsrc/static/engine/compatibility/24c7b1434070dbe01fa83c6a48926ed9.mhk
deleted file mode 100644
index b0b19900a..000000000
--- a/wadsrc/static/engine/compatibility/24c7b1434070dbe01fa83c6a48926ed9.mhk
+++ /dev/null
@@ -1,2 +0,0 @@
-// RR E1L1.map sector bleeds into another area.
-sector 47 split 367 375
diff --git a/wadsrc/static/engine/compatibility/25d4164814f10cd71d26d52d494c4fb8.mhk b/wadsrc/static/engine/compatibility/25d4164814f10cd71d26d52d494c4fb8.mhk
deleted file mode 100644
index f1999796f..000000000
--- a/wadsrc/static/engine/compatibility/25d4164814f10cd71d26d52d494c4fb8.mhk
+++ /dev/null
@@ -1,2 +0,0 @@
-// Wanton Destruction $auto.map - workaround for sector object overlapping with an outer wall.
-sector 152 dontclip
diff --git a/wadsrc/static/engine/compatibility/2bac4971499306ee6c86462e6a03dae8.mhk b/wadsrc/static/engine/compatibility/2bac4971499306ee6c86462e6a03dae8.mhk
deleted file mode 100644
index ba819ff93..000000000
--- a/wadsrc/static/engine/compatibility/2bac4971499306ee6c86462e6a03dae8.mhk
+++ /dev/null
@@ -1,4 +0,0 @@
-// bad sky setting in WT's $volcano.map (original version)
-sector 118 clearflags ceiling 1
-sector 57 clearflags ceiling 1
-sector 281 clearflags ceiling 1
diff --git a/wadsrc/static/engine/compatibility/491a04a732cd5aa253703216ff2feff4.mhk b/wadsrc/static/engine/compatibility/491a04a732cd5aa253703216ff2feff4.mhk
deleted file mode 100644
index e4ce92728..000000000
--- a/wadsrc/static/engine/compatibility/491a04a732cd5aa253703216ff2feff4.mhk
+++ /dev/null
@@ -1,2 +0,0 @@
-// missing texture in RR E1L2.
-wall 3312 setflags 2
diff --git a/wadsrc/static/engine/compatibility/4f2233ed8fb32f6a3deebc7803dbed69.mhk b/wadsrc/static/engine/compatibility/4f2233ed8fb32f6a3deebc7803dbed69.mhk
deleted file mode 100644
index dcfb54fc5..000000000
--- a/wadsrc/static/engine/compatibility/4f2233ed8fb32f6a3deebc7803dbed69.mhk
+++ /dev/null
@@ -1,3 +0,0 @@
-// SW $plax1.map sector bleeds into another area.
-sector 64 split 281 283
-
diff --git a/wadsrc/static/engine/compatibility/5e49c7f6c496e337d59d0c072ed1879b.mhk b/wadsrc/static/engine/compatibility/5e49c7f6c496e337d59d0c072ed1879b.mhk
deleted file mode 100644
index f50cd8af8..000000000
--- a/wadsrc/static/engine/compatibility/5e49c7f6c496e337d59d0c072ed1879b.mhk
+++ /dev/null
@@ -1,3 +0,0 @@
-// SW $bath.ap sector bleeds into another area.
-sector 198 split 1105 1125
-
diff --git a/wadsrc/static/engine/compatibility/67207fb90130ad561479301c0970c7ba.mhk b/wadsrc/static/engine/compatibility/67207fb90130ad561479301c0970c7ba.mhk
deleted file mode 100644
index 388eced27..000000000
--- a/wadsrc/static/engine/compatibility/67207fb90130ad561479301c0970c7ba.mhk
+++ /dev/null
@@ -1,4 +0,0 @@
-// bad sky setting in WT's $volcano.map (fixed version)
-sector 118 clearflags ceiling 1
-sector 57 clearflags ceiling 1
-sector 281 clearflags ceiling 1
diff --git a/wadsrc/static/engine/compatibility/745182e393945e0d308e8e0a5ee80c3c.mhk b/wadsrc/static/engine/compatibility/745182e393945e0d308e8e0a5ee80c3c.mhk
deleted file mode 100644
index a3906bbb4..000000000
--- a/wadsrc/static/engine/compatibility/745182e393945e0d308e8e0a5ee80c3c.mhk
+++ /dev/null
@@ -1,2 +0,0 @@
-// SW's Last Warrior level 4. Do not make the serpent's death end the game. The menu has no second episode so this needs to continue.
-sw_serp_continue
diff --git a/wadsrc/static/engine/compatibility/b4ee363e9d15adc5c9becd01520acd23.mhk b/wadsrc/static/engine/compatibility/b4ee363e9d15adc5c9becd01520acd23.mhk
deleted file mode 100644
index 8eb89748a..000000000
--- a/wadsrc/static/engine/compatibility/b4ee363e9d15adc5c9becd01520acd23.mhk
+++ /dev/null
@@ -1,3 +0,0 @@
-// SW $outpost.map
-// silence a misplaced and *very* annoying ambient sound.
-sprite 442 lotag -1
diff --git a/wadsrc/static/engine/compatibility/c3bfb6a6e7cded2e5fe16cea86632d79.mhk b/wadsrc/static/engine/compatibility/c3bfb6a6e7cded2e5fe16cea86632d79.mhk
deleted file mode 100644
index 5d24c10b7..000000000
--- a/wadsrc/static/engine/compatibility/c3bfb6a6e7cded2e5fe16cea86632d79.mhk
+++ /dev/null
@@ -1,2 +0,0 @@
-// CP07 sector bleeds into another area.
-sector 33 split 192 196
diff --git a/wadsrc/static/engine/compatibility/c6f9e49e397c0b424e8030abc23ac003.mhk b/wadsrc/static/engine/compatibility/c6f9e49e397c0b424e8030abc23ac003.mhk
deleted file mode 100644
index 6b7284136..000000000
--- a/wadsrc/static/engine/compatibility/c6f9e49e397c0b424e8030abc23ac003.mhk
+++ /dev/null
@@ -1,3 +0,0 @@
-// flip inverted keyholes in TD's $shore.map
-sprite 298 clearflags 8
-sprite 307 clearflags 8
diff --git a/wadsrc/static/engine/compatibility/ef6331237eb36c84a4f7b9f5c3cd225d.mhk b/wadsrc/static/engine/compatibility/ef6331237eb36c84a4f7b9f5c3cd225d.mhk
deleted file mode 100644
index dd4806a2d..000000000
--- a/wadsrc/static/engine/compatibility/ef6331237eb36c84a4f7b9f5c3cd225d.mhk
+++ /dev/null
@@ -1,2 +0,0 @@
-// flip the inverted card reader in TD's level 10.
-sprite 179 clearflags 12
diff --git a/wadsrc/static/zscript/level_compatibility.zs b/wadsrc/static/zscript/level_compatibility.zs
index 52192b199..70c2264fe 100644
--- a/wadsrc/static/zscript/level_compatibility.zs
+++ b/wadsrc/static/zscript/level_compatibility.zs
@@ -7,6 +7,64 @@ class LevelCompatibility : LevelPostProcessor
 		{			
 			case 'none':
 				return;
+				
+			case 'c3bfb6a6e7cded2e5fe16cea86632d79':	// CP07
+				SplitSector(33, 192, 196);				// sector bleeds into another area.
+				break;
+
+			case '24c7b1434070dbe01fa83c6a48926ed9': 	// RR E1L1.map 
+				SplitSector(47, 367, 375);				// sector bleeds into another area.
+				wall[4592].dragpoint((1615., -2715.));	// fix overlapping sectors
+				break;
+				
+			case 'd7bf49213531cd2607e0459b950ac454':	// RR E2L7.map
+				// need to add a sprite with picnum 11 (RRJAILDOOR) lotag = 48, hitag = 32, sector = 534
+				// see premap_r.cpp, line 477.
+				break;
+
+			case '491a04a732cd5aa253703216ff2feff4':	// RR E1L2.map
+				wall[3312].cstat |= CSTAT_WALL_BOTTOM_SWAP; // missing lower texture .
+				break;
+				
+			case '4f2233ed8fb32f6a3deebc7803dbed69':	// SW $plax.map
+				SplitSector(64, 281, 283);				// sector bleeds into another area.
+				break;
+
+			case '5e49c7f6c496e337d59d0c072ed1879b':	// SW $bath.map
+				SplitSector(198, 1105, 1125);			// sector bleeds into another area.
+				break;
+
+			case 'b4ee363e9d15adc5c9becd01520acd23':	// SW $outpost.map
+				SetSpriteLotag(442, -1);				// silence a misplaced and *very* annoying ambient sound.
+				break;
+
+			case '25d4164814f10cd71d26d52d494c4fb8':	// WT $auto.map 
+				sector[152].exflags |= SECTOREX_DONTCLIP;	// workaround for sector object overlapping with an outer wall.
+				break;
+
+			case '2bac4971499306ee6c86462e6a03dae8':	// WT $volcano.map (original version)
+			case '67207fb90130ad561479301c0970c7ba':	// WT $volcano.map (fixed version)
+				sector[118].ceilingstat &= ~CSTAT_SECTOR_SKY;
+				sector[57].ceilingstat &= ~CSTAT_SECTOR_SKY;
+				sector[281].ceilingstat &= ~CSTAT_SECTOR_SKY;
+				break;
+				
+			case '745182e393945e0d308e8e0a5ee80c3c': 	// SW Last Warrior level 4. 
+				sw_serp_continue();						// Do not make the serpent's death end the game. The menu has no second episode so this needs to continue.
+				break;
+				
+			case 'c6f9e49e397c0b424e8030abc23ac003':	// TD $shore.map
+				ChangeSpriteFlags(298, CSTAT_SPRITE_YFLIP, 0);	// flip inverted keyhole
+				ChangeSpriteFlags(307, CSTAT_SPRITE_YFLIP, 0);	// flip inverted keyhole
+				break;
+
+			case 'ef6331237eb36c84a4f7b9f5c3cd225d':	// TD level 10
+				ChangeSpriteFlags(179, CSTAT_SPRITE_XFLIP | CSTAT_SPRITE_YFLIP, 0);	// flip the inverted card reader
+				break;
+
+
+
+			
 		}
 	}
 }
diff --git a/wadsrc/static/zscript/level_postprocessor.zs b/wadsrc/static/zscript/level_postprocessor.zs
index 9af905a9d..02ec4cab0 100644
--- a/wadsrc/static/zscript/level_postprocessor.zs
+++ b/wadsrc/static/zscript/level_postprocessor.zs
@@ -7,4 +7,6 @@ class LevelPostProcessor native play
 
 	protected native void SetSpriteLotag(int sprite, int tag);
 	protected native void ChangeSpriteFlags(int sprite, int set, int clear);
+	protected native void sw_serp_continue();
+	protected native void SplitSector(int sect, int wal1, int wal2);
 }
diff --git a/wadsrc/static/zscript/maptypes.zs b/wadsrc/static/zscript/maptypes.zs
index 594ff4ec7..1e640bd31 100644
--- a/wadsrc/static/zscript/maptypes.zs
+++ b/wadsrc/static/zscript/maptypes.zs
@@ -99,6 +99,13 @@ enum ETSprFlags
 	TSPR_SLOPESPRITE = 8,       // render as sloped sprite
 }
 
+enum ESectorExBits
+{
+	SECTOREX_CLOUDSCROLL			= 1,
+	SECTOREX_DRAGGED				= 2,
+	SECTOREX_DONTCLIP				= 4,
+};
+
 
 
 //=============================================================================
@@ -262,6 +269,7 @@ struct walltype native
 
 	native double Length();
 	native void move(Vector2 vec);
+	native void dragpoint(Vector2 vec);
 }
 
 //=============================================================================