diff --git a/specs/udmf_zdoom.txt b/specs/udmf_zdoom.txt
index 9e4df54729d..4f73fa9bd59 100644
--- a/specs/udmf_zdoom.txt
+++ b/specs/udmf_zdoom.txt
@@ -307,8 +307,6 @@ Note: All <bool> fields default to false unless mentioned otherwise.
       leakiness = <int>;              // Probability of leaking through radiation suit (0 = never, 256 = always), default = 0.
       damageterraineffect = <bool>;   // Will spawn a terrain splash when damage is inflicted. Default = false.
       damagehazard = <bool>;          // Changes damage model to Strife's delayed damage for the given sector. Default = false.
-      hurtmonsters = <bool>;          // Non-players like monsters and decorations are hurt by this sector in the same manner as player. Doesn't work with damagehazard.
-      harminair = <bool>;             // Actors in this sector are harmed by the damage effects of the floor even if they aren't touching it.
       floorterrain = <string>;        // Sets the terrain for the sector's floor. Default = 'use the flat texture's terrain definition.'
       ceilingterrain = <string>;      // Sets the terrain for the sector's ceiling. Default = 'use the flat texture's terrain definition.'
       floor_reflect = <float>;        // reflectiveness of floor (OpenGL only, not functional on sloped sectors)
diff --git a/src/gamedata/r_defs.h b/src/gamedata/r_defs.h
index d6453b6f8ad..943893c66a8 100644
--- a/src/gamedata/r_defs.h
+++ b/src/gamedata/r_defs.h
@@ -504,8 +504,6 @@ enum
 	SECMF_OVERLAPPING		= 512,	// floor and ceiling overlap and require special renderer action.
 	SECMF_NOSKYWALLS		= 1024,	// Do not draw "sky walls"
 	SECMF_LIFT				= 2048,	// For MBF monster AI
-	SECMF_HURTMONSTERS		= 4096, // Monsters in this sector are hurt like players.
-	SECMF_HARMINAIR			= 8192, // Actors in this sector are also hurt mid-air.
 };
 
 enum
diff --git a/src/maploader/udmf.cpp b/src/maploader/udmf.cpp
index 1fd9869c325..9748e082f6c 100644
--- a/src/maploader/udmf.cpp
+++ b/src/maploader/udmf.cpp
@@ -1979,14 +1979,6 @@ class UDMFParser : public UDMFParserBase
 					Flag(sec->Flags, SECF_HAZARD, key);
 					break;
 
-				case NAME_hurtmonsters:
-					Flag(sec->MoreFlags, SECMF_HURTMONSTERS, key);
-					break;
-
-				case NAME_harminair:
-					Flag(sec->MoreFlags, SECMF_HARMINAIR, key);
-					break;
-
 				case NAME_floorterrain:
 					sec->terrainnum[sector_t::floor] = P_FindTerrain(CheckString(key));
 					break;
diff --git a/src/namedef_custom.h b/src/namedef_custom.h
index dbf94dbafc5..dd2e0066d47 100644
--- a/src/namedef_custom.h
+++ b/src/namedef_custom.h
@@ -810,8 +810,6 @@ xx(damageinterval)
 xx(leakiness)
 xx(damageterraineffect)
 xx(damagehazard)
-xx(hurtmonsters)
-xx(harminair)
 xx(floorterrain)
 xx(ceilingterrain)
 xx(floor_reflect)
diff --git a/src/playsim/actor.h b/src/playsim/actor.h
index 759d9d26281..d472decad19 100644
--- a/src/playsim/actor.h
+++ b/src/playsim/actor.h
@@ -442,8 +442,7 @@ enum ActorFlag9
 	MF9_DOSHADOWBLOCK			= 0x00000002,	// [inkoalawetrust] Should the monster look for SHADOWBLOCK actors ?
 	MF9_SHADOWBLOCK				= 0x00000004,	// [inkoalawetrust] Actors in the line of fire with this flag trigger the MF_SHADOW aiming penalty.
 	MF9_SHADOWAIMVERT			= 0x00000008,	// [inkoalawetrust] Monster aim is also offset vertically when aiming at shadow actors.
-	MF9_DECOUPLEDANIMATIONS		= 0x00000010,	// [RL0] Decouple model animations from states
-	MF9_NOSECTORDAMAGE			= 0x00000020,	// [inkoalawetrust] Actor ignores any sector-based damage (i.e damaging floors, NOT crushers)
+	MF9_DECOUPLEDANIMATIONS	= 0x00000010,	// [RL0] Decouple model animations from states
 	MF9_ISPUFF					= 0x00000040,	// [AA] Set on actors by P_SpawnPuff
 };
 
diff --git a/src/playsim/p_3dfloors.cpp b/src/playsim/p_3dfloors.cpp
index 505bfa7946b..dd5a2bb0a7e 100644
--- a/src/playsim/p_3dfloors.cpp
+++ b/src/playsim/p_3dfloors.cpp
@@ -198,15 +198,15 @@ void P_Add3DFloor(sector_t* sec, sector_t* sec2, line_t* master, int flags, int
 
 //==========================================================================
 //
-// P_ActorOnSpecial3DFloor
-// Checks to see if an actor is standing on or is inside a 3D floor (water)
+// P_PlayerOnSpecial3DFloor
+// Checks to see if a player is standing on or is inside a 3D floor (water)
 // and applies any specials..
 //
 //==========================================================================
 
-void P_ActorOnSpecial3DFloor(AActor* victim)
+void P_PlayerOnSpecial3DFloor(player_t* player)
 {
-	for(auto rover : victim->Sector->e->XFloor.ffloors)
+	for(auto rover : player->mo->Sector->e->XFloor.ffloors)
 	{
 		if (!(rover->flags & FF_EXISTS)) continue;
 		if (rover->flags & FF_FIX) continue;
@@ -215,22 +215,22 @@ void P_ActorOnSpecial3DFloor(AActor* victim)
 		if(rover->flags & FF_SOLID)
 		{
 			// Player must be on top of the floor to be affected...
-			if(victim->Z() != rover->top.plane->ZatPoint(victim)) continue;
+			if(player->mo->Z() != rover->top.plane->ZatPoint(player->mo)) continue;
 		}
 		else 
 		{
 			//Water and DEATH FOG!!! heh
 			if ((rover->flags & FF_NODAMAGE) ||
-				victim->Z() > rover->top.plane->ZatPoint(victim) ||
-				victim->Top() < rover->bottom.plane->ZatPoint(victim))
+				player->mo->Z() > rover->top.plane->ZatPoint(player->mo) ||
+				player->mo->Top() < rover->bottom.plane->ZatPoint(player->mo))
 				continue;
 		}
 
 		// Apply sector specials
-		P_ActorInSpecialSector(victim, rover->model);
+		P_PlayerInSpecialSector(player, rover->model);
 
 		// Apply flat specials (using the ceiling!)
-		P_ActorOnSpecialFlat(victim, rover->model->GetTerrain(rover->top.isceiling));
+		P_PlayerOnSpecialFlat(player, rover->model->GetTerrain(rover->top.isceiling));
 
 		break;
 	}
diff --git a/src/playsim/p_3dfloors.h b/src/playsim/p_3dfloors.h
index 2dba7f71379..05d222137e9 100644
--- a/src/playsim/p_3dfloors.h
+++ b/src/playsim/p_3dfloors.h
@@ -113,7 +113,8 @@ struct lightlist_t
 
 
 
-void P_ActorOnSpecial3DFloor(AActor* victim);
+class player_t;
+void P_PlayerOnSpecial3DFloor(player_t* player);
 
 bool P_CheckFor3DFloorHit(AActor * mo, double z, bool trigger);
 bool P_CheckFor3DCeilingHit(AActor * mo, double z, bool trigger);
diff --git a/src/playsim/p_mobj.cpp b/src/playsim/p_mobj.cpp
index 8d34e6c73ba..72251ec7923 100644
--- a/src/playsim/p_mobj.cpp
+++ b/src/playsim/p_mobj.cpp
@@ -4435,14 +4435,6 @@ void AActor::Tick ()
 		// must have been removed
 		if (ObjectFlags & OF_EuthanizeMe) return;
 	}
-	//[inkoalawetrust] Genericized level damage handling that makes sector, 3D floor, and TERRAIN flat damage affect monsters and other NPCs too.
-	if (!(flags9 & MF9_NOSECTORDAMAGE) && (player || (player == nullptr && Sector->MoreFlags & SECMF_HURTMONSTERS)))
-	{
-		P_ActorOnSpecial3DFloor(this);
-		P_ActorInSpecialSector(this,Sector);
-		if (!isAbove(Sector->floorplane.ZatPoint(this)) || waterlevel) // Actor must be touching the floor for TERRAIN flats.
-			P_ActorOnSpecialFlat(this, P_GetThingFloorType(this));
-	}
 
 	if (tics != -1)
 	{
diff --git a/src/playsim/p_spec.cpp b/src/playsim/p_spec.cpp
index 9c3fde6f4d6..ab52f285af1 100644
--- a/src/playsim/p_spec.cpp
+++ b/src/playsim/p_spec.cpp
@@ -100,7 +100,7 @@
 #include "c_console.h"
 #include "p_spec_thinkers.h"
 
-static FRandom pr_actorinspecialsector ("ActorInSpecialSector");
+static FRandom pr_playerinspecialsector ("PlayerInSpecialSector");
 
 EXTERN_CVAR(Bool, cl_predict_specials)
 EXTERN_CVAR(Bool, forcewater)
@@ -419,18 +419,21 @@ bool P_PredictLine(line_t *line, AActor *mo, int side, int activationType)
 }
 
 //
-// P_ActorInSpecialSector
+// P_PlayerInSpecialSector
 // Called every tic frame
-//	that the actor origin is in a special sector
+//	that the player origin is in a special sector
 //
-void P_ActorInSpecialSector (AActor *victim, sector_t * sector)
+void P_PlayerInSpecialSector (player_t *player, sector_t * sector)
 {
 	if (sector == NULL)
-		sector = victim->Sector;
-
-	// Falling, not all the way down yet?
-	if (!(sector->MoreFlags & SECMF_HARMINAIR) && !victim->isAtZ(sector->LowestFloorAt(victim)) && !victim->waterlevel)
-		return;
+	{
+		// Falling, not all the way down yet?
+		sector = player->mo->Sector;
+		if (!player->mo->isAtZ(sector->LowestFloorAt(player->mo))
+			&& !player->mo->waterlevel)
+		{
+			return;
+		}
 
 	// Has hit ground.
 
@@ -441,7 +444,7 @@ void P_ActorInSpecialSector (AActor *victim, sector_t * sector)
 	if (sector->damageinterval <= 0)
 		sector->damageinterval = 32; // repair invalid damageinterval values
 
-	if (victim->player && sector->Flags & (SECF_EXIT1 | SECF_EXIT2))
+	if (sector->Flags & (SECF_EXIT1 | SECF_EXIT2))
 	{
 		for (int i = 0; i < MAXPLAYERS; i++)
 			if (playeringame[i])
@@ -460,7 +463,7 @@ void P_ActorInSpecialSector (AActor *victim, sector_t * sector)
 		// different damage types yet, so that's not happening for now.
 		// [MK] account for subclasses that may have "Full" protection (i.e.: prevent leaky damage)
 		int ironfeet = 0;
-		for (auto i = victim->Inventory; i != NULL; i = i->Inventory)
+		for (auto i = player->mo->Inventory; i != NULL; i = i->Inventory)
 		{
 			if (i->IsKindOf(NAME_PowerIronFeet))
 			{
@@ -472,28 +475,28 @@ void P_ActorInSpecialSector (AActor *victim, sector_t * sector)
 			}
 		}
 
-		if (victim->player && sector->Flags & SECF_ENDGODMODE) victim->player->cheats &= ~CF_GODMODE;
-		if ((ironfeet == 0 || (ironfeet < 2 && pr_actorinspecialsector() < sector->leakydamage)))
+		if (sector->Flags & SECF_ENDGODMODE) player->cheats &= ~CF_GODMODE;
+		if ((ironfeet == 0 || (ironfeet < 2 && pr_playerinspecialsector() < sector->leakydamage)))
 		{
-			if (victim->player && sector->Flags & SECF_HAZARD)
+			if (sector->Flags & SECF_HAZARD)
 			{
-				victim->player->hazardcount += sector->damageamount;
-				victim->player->hazardtype = sector->damagetype;
-				victim->player->hazardinterval = sector->damageinterval;
+				player->hazardcount += sector->damageamount;
+				player->hazardtype = sector->damagetype;
+				player->hazardinterval = sector->damageinterval;
 			}
 			else if (Level->time % sector->damageinterval == 0)
 			{
-				if (!(victim->player && victim->player->cheats & (CF_GODMODE | CF_GODMODE2)))
+				if (!(player->cheats & (CF_GODMODE | CF_GODMODE2)))
 				{
-					P_DamageMobj(victim, NULL, NULL, sector->damageamount, sector->damagetype);
+					P_DamageMobj(player->mo, NULL, NULL, sector->damageamount, sector->damagetype);
 				}
-				if (victim->player && (sector->Flags & SECF_ENDLEVEL) && victim->player->health <= 10 && (!deathmatch || !(dmflags & DF_NO_EXIT)))
+				if ((sector->Flags & SECF_ENDLEVEL) && player->health <= 10 && (!deathmatch || !(dmflags & DF_NO_EXIT)))
 				{
 					Level->ExitLevel(0, false);
 				}
 				if (sector->Flags & SECF_DMGTERRAINFX)
 				{
-					P_HitWater(victim, victim->Sector, victim->Pos(), false, true, true);
+					P_HitWater(player->mo, player->mo->Sector, player->mo->Pos(), false, true, true);
 				}
 			}
 		}
@@ -502,14 +505,14 @@ void P_ActorInSpecialSector (AActor *victim, sector_t * sector)
 	{
 		if (Level->time % sector->damageinterval == 0)
 		{
-			P_GiveBody(victim, -sector->damageamount, 100);
+			P_GiveBody(player->mo, -sector->damageamount, 100);
 		}
 	}
 
-	if (victim->player && sector->isSecret())
+	if (sector->isSecret())
 	{
 		sector->ClearSecret();
-		P_GiveSecret(Level, victim, true, true, sector->Index());
+		P_GiveSecret(Level, player->mo, true, true, sector->Index());
 	}
 }
 
@@ -648,13 +651,13 @@ DEFINE_ACTION_FUNCTION(FLevelLocals, GiveSecret)
 
 //============================================================================
 //
-// P_ActorOnSpecialFlat
+// P_PlayerOnSpecialFlat
 //
 //============================================================================
 
-void P_ActorOnSpecialFlat (AActor *victim, int floorType)
+void P_PlayerOnSpecialFlat (player_t *player, int floorType)
 {
-	auto Level = victim->Level;
+	auto Level = player->mo->Level;
 
 	if (Terrains[floorType].DamageAmount &&
 		!(Level->time % (Terrains[floorType].DamageTimeMask+1)))
@@ -664,7 +667,7 @@ void P_ActorOnSpecialFlat (AActor *victim, int floorType)
 		if (Terrains[floorType].AllowProtection)
 		{
 			auto pitype = PClass::FindActor(NAME_PowerIronFeet);
-			for (ironfeet = victim->Inventory; ironfeet != NULL; ironfeet = ironfeet->Inventory)
+			for (ironfeet = player->mo->Inventory; ironfeet != NULL; ironfeet = ironfeet->Inventory)
 			{
 				if (ironfeet->IsKindOf (pitype))
 					break;
@@ -674,18 +677,20 @@ void P_ActorOnSpecialFlat (AActor *victim, int floorType)
 		int damage = 0;
 		if (ironfeet == NULL)
 		{
-			damage = P_DamageMobj (victim, NULL, NULL, Terrains[floorType].DamageAmount,
+			damage = P_DamageMobj (player->mo, NULL, NULL, Terrains[floorType].DamageAmount,
 				Terrains[floorType].DamageMOD);
 		}
 		if (damage > 0 && Terrains[floorType].Splash != -1)
 		{
-			S_Sound (victim, CHAN_AUTO, 0,
+			S_Sound (player->mo, CHAN_AUTO, 0,
 				Splashes[Terrains[floorType].Splash].NormalSplashSound, 1,
 				ATTN_IDLE);
 		}
 	}
 }
 
+
+
 //
 // P_UpdateSpecials
 // Animate planes, scroll walls, etc.
diff --git a/src/playsim/p_spec.h b/src/playsim/p_spec.h
index ebb5d93f913..cc7d990a97c 100644
--- a/src/playsim/p_spec.h
+++ b/src/playsim/p_spec.h
@@ -90,8 +90,8 @@ bool	P_ActivateLine (line_t *ld, AActor *mo, int side, int activationType, DVect
 bool	P_TestActivateLine (line_t *ld, AActor *mo, int side, int activationType, DVector3 *optpos = NULL);
 bool	P_PredictLine (line_t *ld, AActor *mo, int side, int activationType);
 
-void 	P_ActorInSpecialSector (AActor *victim, sector_t * sector=NULL);
-void	P_ActorOnSpecialFlat (AActor *victim, int floorType);
+void 	P_PlayerInSpecialSector (player_t *player, sector_t * sector=NULL);
+void	P_PlayerOnSpecialFlat (player_t *player, int floorType);
 void	P_SectorDamage(FLevelLocals *Level, int tag, int amount, FName type, PClassActor *protectClass, int flags);
 void	P_SetSectorFriction (FLevelLocals *level, int tag, int amount, bool alterFlag);
 double FrictionToMoveFactor(double friction);
diff --git a/src/playsim/p_user.cpp b/src/playsim/p_user.cpp
index a98a7c523cd..d3294ffd605 100644
--- a/src/playsim/p_user.cpp
+++ b/src/playsim/p_user.cpp
@@ -1204,6 +1204,15 @@ DEFINE_ACTION_FUNCTION(APlayerPawn, CheckMusicChange)
 
 void P_CheckEnvironment(player_t *player)
 {
+	P_PlayerOnSpecial3DFloor(player);
+	P_PlayerInSpecialSector(player);
+
+	if (!player->mo->isAbove(player->mo->Sector->floorplane.ZatPoint(player->mo)) ||
+		player->mo->waterlevel)
+	{
+		// Player must be touching the floor
+		P_PlayerOnSpecialFlat(player, P_GetThingFloorType(player->mo));
+	}
 	if (player->mo->Vel.Z <= -player->mo->FloatVar(NAME_FallingScreamMinSpeed) &&
 		player->mo->Vel.Z >= -player->mo->FloatVar(NAME_FallingScreamMaxSpeed) && player->mo->alternative == nullptr &&
 		player->mo->waterlevel == 0)
diff --git a/src/scripting/thingdef_data.cpp b/src/scripting/thingdef_data.cpp
index 129c06b7869..be7c299edd3 100644
--- a/src/scripting/thingdef_data.cpp
+++ b/src/scripting/thingdef_data.cpp
@@ -351,7 +351,6 @@ static FFlagDef ActorFlagDefs[]=
 	DEFINE_FLAG(MF9, SHADOWBLOCK, AActor, flags9),
 	DEFINE_FLAG(MF9, SHADOWAIMVERT, AActor, flags9),
 	DEFINE_FLAG(MF9, DECOUPLEDANIMATIONS, AActor, flags9),
-	DEFINE_FLAG(MF9, NOSECTORDAMAGE, AActor, flags9),
 	DEFINE_PROTECTED_FLAG(MF9, ISPUFF, AActor, flags9), //[AA] was spawned by SpawnPuff
 
 	// Effect flags
diff --git a/wadsrc/static/zscript/mapdata.zs b/wadsrc/static/zscript/mapdata.zs
index 06a7bf3eadf..5d45563eb39 100644
--- a/wadsrc/static/zscript/mapdata.zs
+++ b/wadsrc/static/zscript/mapdata.zs
@@ -435,11 +435,6 @@ struct Sector native play
 		SECMF_UNDERWATERMASK	= 32+64,
 		SECMF_DRAWN			= 128,	// sector has been drawn at least once
 		SECMF_HIDDEN			= 256,	// Do not draw on textured automap
-		SECMF_OVERLAPPING		= 512,	// floor and ceiling overlap and require special renderer action.
-		SECMF_NOSKYWALLS		= 1024,	// Do not draw "sky walls"
-		SECMF_LIFT				= 2048,	// For MBF monster AI
-		SECMF_HURTMONSTERS		= 4096, // Monsters in this sector are hurt like players.
-		SECMF_HARMINAIR			= 8192, // Actors in this sector are also hurt mid-air.
 	}
 	native uint16		MoreFlags;
 	
@@ -457,9 +452,6 @@ struct Sector native play
 		SECF_ENDLEVEL		= 512,	// ends level when health goes below 10
 		SECF_HAZARD			= 1024,	// Change to Strife's delayed damage handling.
 		SECF_NOATTACK		= 2048,	// monsters cannot start attacks in this sector.
-		SECF_EXIT1			= 4096,
-		SECF_EXIT2			= 8192,
-		SECF_KILLMONSTERS	= 16384,// Monsters in this sector are instantly killed.
 
 		SECF_WASSECRET		= 1 << 30,	// a secret that was discovered
 		SECF_SECRET			= 1 << 31,	// a secret sector