diff --git a/src/compatibility.cpp b/src/compatibility.cpp
index 95d178635..2a721c33f 100644
--- a/src/compatibility.cpp
+++ b/src/compatibility.cpp
@@ -131,6 +131,7 @@ static FCompatOption Options[] =
 	{ "polyobj",				COMPATF_POLYOBJ, SLOT_COMPAT },
 	{ "maskedmidtex",			COMPATF_MASKEDMIDTEX, SLOT_COMPAT },
 	{ "badangles",				COMPATF2_BADANGLES, SLOT_COMPAT2 },
+	{ "floormove",				COMPATF2_FLOORMOVE, SLOT_COMPAT2 },
 
 	{ NULL, 0, 0 }
 };
diff --git a/src/d_main.cpp b/src/d_main.cpp
index 632a6729a..b3c8f5f56 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -562,6 +562,7 @@ CUSTOM_CVAR(Int, compatmode, 0, CVAR_ARCHIVE|CVAR_NOINITCALL)
 		v = COMPATF_SHORTTEX|COMPATF_STAIRINDEX|COMPATF_USEBLOCKING|COMPATF_NODOORLIGHT|COMPATF_SPRITESORT|
 			COMPATF_TRACE|COMPATF_MISSILECLIP|COMPATF_SOUNDTARGET|COMPATF_DEHHEALTH|COMPATF_CROSSDROPOFF|
 			COMPATF_LIGHT;
+		w= COMPATF2_FLOORMOVE;
 		break;
 
 	case 2:	// same as 1 but stricter (NO_PASSMOBJ and INVISIBILITY are also set)
@@ -569,7 +570,7 @@ CUSTOM_CVAR(Int, compatmode, 0, CVAR_ARCHIVE|CVAR_NOINITCALL)
 			COMPATF_TRACE|COMPATF_MISSILECLIP|COMPATF_SOUNDTARGET|COMPATF_NO_PASSMOBJ|COMPATF_LIMITPAIN|
 			COMPATF_DEHHEALTH|COMPATF_INVISIBILITY|COMPATF_CROSSDROPOFF|COMPATF_CORPSEGIBS|COMPATF_HITSCAN|
 			COMPATF_WALLRUN|COMPATF_NOTOSSDROPS|COMPATF_LIGHT|COMPATF_MASKEDMIDTEX;
-		w = COMPATF2_BADANGLES;
+		w = COMPATF2_BADANGLES|COMPATF2_FLOORMOVE;
 		break;
 
 	case 3: // Boom compat mode
@@ -628,6 +629,7 @@ CVAR (Flag, compat_light,				compatflags,  COMPATF_LIGHT);
 CVAR (Flag, compat_polyobj,				compatflags,  COMPATF_POLYOBJ);
 CVAR (Flag, compat_maskedmidtex,		compatflags,  COMPATF_MASKEDMIDTEX);
 CVAR (Flag, compat_badangles,			compatflags2, COMPATF2_BADANGLES);
+CVAR (Flag, compat_floormove,			compatflags2, COMPATF2_FLOORMOVE);
 
 //==========================================================================
 //
diff --git a/src/doomdef.h b/src/doomdef.h
index 538f084d7..114f8c701 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -336,6 +336,7 @@ enum
 	COMPATF_MASKEDMIDTEX	= 1 << 31,	// Ignore compositing when drawing masked midtextures
 
 	COMPATF2_BADANGLES		= 1 << 0,	// It is impossible to face directly NSEW.
+	COMPATF2_FLOORMOVE		= 1 << 1,	// Use the same floor motion behavior as Doom.
 };
 
 // Emulate old bugs for select maps. These are not exposed by a cvar
diff --git a/src/dsectoreffect.cpp b/src/dsectoreffect.cpp
index e474bb841..6732a19dc 100644
--- a/src/dsectoreffect.cpp
+++ b/src/dsectoreffect.cpp
@@ -223,7 +223,7 @@ DMover::EResult DMover::MovePlane (fixed_t speed, fixed_t dest, int crush,
 			//destheight = (dest < m_Sector->ceilingheight) ? dest : m_Sector->ceilingheight;
 			if ((m_Sector->ceilingplane.a | m_Sector->ceilingplane.b |
 				 m_Sector->floorplane.a | m_Sector->floorplane.b) == 0 &&
-				-dest > m_Sector->ceilingplane.d)
+				(!(i_compatflags2 & COMPATF2_FLOORMOVE) && -dest > m_Sector->ceilingplane.d))
 			{
 				dest = -m_Sector->ceilingplane.d;
 			}
@@ -292,7 +292,7 @@ DMover::EResult DMover::MovePlane (fixed_t speed, fixed_t dest, int crush,
 			//destheight = (dest > m_Sector->floorheight) ? dest : m_Sector->floorheight;
 			if ((m_Sector->ceilingplane.a | m_Sector->ceilingplane.b |
 				 m_Sector->floorplane.a | m_Sector->floorplane.b) == 0 &&
-				dest < -m_Sector->floorplane.d)
+				(!(i_compatflags2 & COMPATF2_FLOORMOVE) && dest < -m_Sector->floorplane.d))
 			{
 				dest = -m_Sector->floorplane.d;
 			}
diff --git a/src/g_mapinfo.cpp b/src/g_mapinfo.cpp
index 3b6e6eb92..710470bbd 100644
--- a/src/g_mapinfo.cpp
+++ b/src/g_mapinfo.cpp
@@ -1273,6 +1273,7 @@ MapFlagHandlers[] =
 	{ "compat_polyobj",					MITYPE_COMPATFLAG, COMPATF_POLYOBJ, 0 },
 	{ "compat_maskedmidtex",			MITYPE_COMPATFLAG, COMPATF_MASKEDMIDTEX, 0 },
 	{ "compat_badangles",				MITYPE_COMPATFLAG, 0, COMPATF2_BADANGLES },
+	{ "compat_floormove",				MITYPE_COMPATFLAG, 0, COMPATF2_FLOORMOVE },
 	{ "cd_start_track",					MITYPE_EATNEXT,	0, 0 },
 	{ "cd_end1_track",					MITYPE_EATNEXT,	0, 0 },
 	{ "cd_end2_track",					MITYPE_EATNEXT,	0, 0 },
diff --git a/wadsrc/static/compatibility.txt b/wadsrc/static/compatibility.txt
index 64ecd112b..531e89a4d 100644
--- a/wadsrc/static/compatibility.txt
+++ b/wadsrc/static/compatibility.txt
@@ -171,3 +171,8 @@ E2B5D1400279335811C1C1C0B437D9C8 // Deathknights of the Dark Citadel, map54
 {
 	clearlinespecial 66
 }
+
+8FA29398776146189396AA1AC6BB9E13 // Roger Ritenour's Phobos map03
+{
+	floormove
+}
diff --git a/wadsrc/static/menudef.txt b/wadsrc/static/menudef.txt
index 2eab5628b..6a99b4459 100644
--- a/wadsrc/static/menudef.txt
+++ b/wadsrc/static/menudef.txt
@@ -1220,7 +1220,8 @@ OptionMenu "CompatibilityOptions"
 	Option "Cripple sound for silent BFG trick",		"compat_soundslots", "YesNo"
 	Option "Draw polyobjects like Hexen",				"compat_POLYOBJ", "YesNo"
 	Option "Ignore Y offsets on masked midtextures",	"compat_MASKEDMIDTEX", "YesNo"
-	Option "Cannot travel straight NSEW",			"compat_badangles", "YesNo"
+	Option "Cannot travel straight NSEW",				"compat_badangles", "YesNo"
+	Option "Use Doom's floor motion behavior",			"compat_floormove", "YesNo"
 	
 	Class "CompatibilityMenu"
 }