diff --git a/src/dehacked.c b/src/dehacked.c
index 961ab2d7c..ba08d2e09 100644
--- a/src/dehacked.c
+++ b/src/dehacked.c
@@ -1164,6 +1164,8 @@ static void readlevelheader(MYFILE *f, INT32 num)
 			}*/
 			else if (fastcmp(word, "MOBJSCALE"))
 				mapheaderinfo[num-1]->mobj_scale = get_number(word2);
+			else if (fastcmp(word, "DEFAULTWAYPOINTRADIUS"))
+				mapheaderinfo[num-1]->default_waypoint_radius = get_number(word2);
 
 			// Individual triggers for level flags, for ease of use (and 2.0 compatibility)
 			else if (fastcmp(word, "SCRIPTISFILE"))
diff --git a/src/doomstat.h b/src/doomstat.h
index 9971fdfc5..80a351d22 100644
--- a/src/doomstat.h
+++ b/src/doomstat.h
@@ -290,6 +290,7 @@ typedef struct
 	// SRB2kart
 	//boolean automap;    ///< Displays a level's white map outline in modified games
 	fixed_t mobj_scale; ///< Replacement for TOL_ERZ3
+	fixed_t default_waypoint_radius; ///< 0 is a special value for DEFAULT_WAYPOINT_RADIUS, but scaled with mobjscale
 
 	// Music stuff.
 	UINT32 musinterfadeout;  ///< Fade out level music on intermission screen in milliseconds
diff --git a/src/k_kart.c b/src/k_kart.c
index 2b81bd797..9ded7a291 100644
--- a/src/k_kart.c
+++ b/src/k_kart.c
@@ -6375,6 +6375,11 @@ static INT16 K_GetKartDriftValue(player_t *player, fixed_t countersteer)
 		basedrift += (basedrift / greasetics) * player->kartstuff[k_tiregrease];
 	}
 
+	if (player->mo->eflags & (MFE_UNDERWATER|MFE_TOUCHWATER))
+	{
+		countersteer = 3*countersteer/2;
+	}
+
 	return basedrift + (FixedMul(driftadjust * FRACUNIT, countersteer) / FRACUNIT);
 }
 
@@ -6410,6 +6415,11 @@ INT16 K_GetKartTurnValue(player_t *player, INT16 turnvalue)
 		turnvalue = 5*turnvalue/4;
 	}
 
+	if (player->mo->eflags & (MFE_UNDERWATER|MFE_TOUCHWATER))
+	{
+		turnvalue = 3*turnvalue/2;
+	}
+
 	turnvalue = FixedMul(turnvalue * FRACUNIT, weightadjust) / FRACUNIT; // Weight has a small effect on turning
 
 	return turnvalue;
@@ -7530,6 +7540,9 @@ void K_MoveKartPlayer(player_t *player, boolean onground)
 		if (G_BattleGametype() && player->kartstuff[k_bumper] <= 0)
 			player->mo->friction += 1228;
 
+		if (player->mo->eflags & (MFE_UNDERWATER|MFE_TOUCHWATER))
+			player->mo->friction += 614;
+
 		// Wipeout slowdown
 		if (player->kartstuff[k_spinouttimer] && player->kartstuff[k_wipeoutslow])
 		{
diff --git a/src/k_waypoint.c b/src/k_waypoint.c
index f32cf68b0..d320d4a19 100644
--- a/src/k_waypoint.c
+++ b/src/k_waypoint.c
@@ -1937,8 +1937,7 @@ void K_AdjustWaypointsParameters (void)
 						waypointmobj;
 						waypointmobj = waypointmobj->tracer
 				){
-					if (K_AnchorWaypointRadius(waypointmobj, anchor))
-						break;
+					K_AnchorWaypointRadius(waypointmobj, anchor);
 				}
 			}
 		}
diff --git a/src/k_waypoint.h b/src/k_waypoint.h
index 0017c443e..41230b49b 100644
--- a/src/k_waypoint.h
+++ b/src/k_waypoint.h
@@ -18,6 +18,8 @@
 #include "p_mobj.h"
 #include "k_pathfind.h"
 
+#define DEFAULT_WAYPOINT_RADIUS (384)
+
 typedef struct waypoint_s
 {
 	mobj_t             *mobj;
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 174cb0322..8d474a86e 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -1249,29 +1249,45 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 	}
 
 	// Less gravity underwater.
-	if (mo->eflags & MFE_UNDERWATER && !goopgravity)
-		gravityadd = gravityadd/3;
+	if ((mo->eflags & MFE_UNDERWATER) && !goopgravity)
+	{
+		if (mo->momz * P_MobjFlip(mo) <= 0)
+		{
+			gravityadd = 4*gravityadd/3;
+		}
+		else
+		{
+			gravityadd = gravityadd/3;
+		}
+	}
 
 	if (mo->player)
 	{
-		//if ((mo->player->pflags & PF_GLIDING)
-		//|| (mo->player->charability == CA_FLY && (mo->player->powers[pw_tailsfly]
-		//	|| (mo->state >= &states[S_PLAY_SPC1] && mo->state <= &states[S_PLAY_SPC4]))))
-		//	gravityadd = gravityadd/3; // less gravity while flying/gliding
 		if (mo->player->climbing || (mo->player->pflags & PF_NIGHTSMODE))
+		{
 			return 0;
+		}
 
 		if (!(mo->flags2 & MF2_OBJECTFLIP) != !(mo->player->powers[pw_gravityboots])) // negated to turn numeric into bool - would be double negated, but not needed if both would be
 		{
 			gravityadd = -gravityadd;
 			mo->eflags ^= MFE_VERTICALFLIP;
 		}
+
 		if (wasflip == !(mo->eflags & MFE_VERTICALFLIP)) // note!! == ! is not equivalent to != here - turns numeric into bool this way
+		{
 			P_PlayerFlip(mo);
+		}
+
 		if (mo->player->kartstuff[k_pogospring])
+		{
 			gravityadd = (5*gravityadd)/2;
+		}
+
 		if (mo->player->kartstuff[k_waterskip])
+		{
 			gravityadd = (4*gravityadd)/3;
+		}
 	}
 	else
 	{
@@ -1279,10 +1295,15 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 		if (mo->flags2 & MF2_OBJECTFLIP)
 		{
 			mo->eflags |= MFE_VERTICALFLIP;
+
 			if (mo->z + mo->height >= mo->ceilingz)
+			{
 				gravityadd = 0;
+			}
 			else if (gravityadd < 0) // Don't sink, only rise up
-				gravityadd *= -1;
+			{
+				gravityadd = -gravityadd;
+			}
 		}
 		else //Otherwise, sort through the other exceptions.
 		{
@@ -1317,7 +1338,7 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 					}
 					break;
 				case MT_WATERDROP:
-					gravityadd >>= 1;
+					gravityadd /= 2;
 					break;
 				case MT_BANANA:
 				case MT_EGGMANITEM:
@@ -1342,7 +1363,9 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 
 	// Goop has slower, reversed gravity
 	if (goopgravity)
+	{
 		gravityadd = -gravityadd/5;
+	}
 
 	gravityadd = FixedMul(gravityadd, mo->scale);
 
@@ -12666,9 +12689,17 @@ ML_NOCLIMB : Direction not controllable
 		break;
 	case MT_WAYPOINT:
 	{
+		const fixed_t mobjscale =
+			mapheaderinfo[gamemap-1]->default_waypoint_radius;
+
 		// Just like MT_SPINMACEPOINT, this now works here too!
 		INT32 line = P_FindSpecialLineFromTag(2000, mthing->angle, -1);
-		mobj->radius = 384*FRACUNIT;
+
+		if (mobjscale == 0)
+			mobj->radius = DEFAULT_WAYPOINT_RADIUS * mapobjectscale;
+		else
+			mobj->radius = mobjscale;
+
 		// Set the radius, mobj z, and mthing z to match what the parameters want
 		if (line != -1)
 		{
diff --git a/src/p_setup.c b/src/p_setup.c
index d9ffeaa3c..2ea730126 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -258,6 +258,8 @@ static void P_ClearSingleMapHeaderInfo(INT16 i)
 	//mapheaderinfo[num]->automap = false;
 	DEH_WriteUndoline("MOBJSCALE", va("%d", mapheaderinfo[num]->mobj_scale), UNDO_NONE);
 	mapheaderinfo[num]->mobj_scale = FRACUNIT;
+	DEH_WriteUndoline("DEFAULTWAYPOINTRADIUS", va("%d", mapheaderinfo[num]->default_waypoint_radius), UNDO_NONE);
+	mapheaderinfo[num]->default_waypoint_radius = 0;
 	// an even further impossibility, delfile custom opts support
 	mapheaderinfo[num]->customopts = NULL;
 	mapheaderinfo[num]->numCustomOptions = 0;