diff --git a/source/games/duke/src/actors.cpp b/source/games/duke/src/actors.cpp
index 4c30249ff..2faf6a034 100644
--- a/source/games/duke/src/actors.cpp
+++ b/source/games/duke/src/actors.cpp
@@ -1004,7 +1004,7 @@ void movetrash(DDukeActor *actor)
 	if (ssp(actor, CLIPMASK0))
 	{
 		makeitfall(actor);
-		if (krand() & 1) actor->spr.zvel -= 256;
+		if (krand() & 1) actor->add_int_zvel(- 256);
 		if (abs(actor->spr.xvel) < 48)
 			actor->spr.xvel += (krand() & 3);
 	}
@@ -2382,7 +2382,7 @@ void shell(DDukeActor* actor, bool morecheck)
 			actor->temp_data[0] &= 3;
 		}
 		if (actor->int_zvel() < 128) actor->add_int_zvel( (gs.gravity / 13)); // 8
-		else actor->spr.zvel -= 64;
+		else actor->add_int_zvel(- 64);
 		if (actor->spr.xvel > 0)
 			actor->spr.xvel -= 4;
 		else actor->spr.xvel = 0;
diff --git a/source/games/duke/src/actors_d.cpp b/source/games/duke/src/actors_d.cpp
index 8e15e7215..532322640 100644
--- a/source/games/duke/src/actors_d.cpp
+++ b/source/games/duke/src/actors_d.cpp
@@ -2400,7 +2400,7 @@ static void greenslime(DDukeActor *actor)
 		if (actor->spr.yrepeat < 40) actor->spr.yrepeat += 8;
 		if (actor->spr.xrepeat > 8) actor->spr.xrepeat -= 4;
 		if (actor->int_zvel() > -(2048 + 1024))
-			actor->spr.zvel -= 348;
+			actor->add_int_zvel(- 348);
 		actor->add_int_z(actor->int_zvel());
 		if (actor->spr.pos.Z < actor->ceilingz + 16)
 		{
@@ -3526,7 +3526,7 @@ void move_d(DDukeActor *actor, int playernum, int xvel)
 	if ((a & jumptoplayer) == jumptoplayer)
 	{
 		if (actor->temp_data[0] < 16)
-			actor->spr.zvel -= bcos(actor->temp_data[0] << 4, -5);
+			actor->add_int_zvel(- bcos(actor->temp_data[0] << 4, -5));
 	}
 
 	if (a & face_player_smart)
diff --git a/source/games/duke/src/actors_r.cpp b/source/games/duke/src/actors_r.cpp
index a3c441b75..6016a494f 100644
--- a/source/games/duke/src/actors_r.cpp
+++ b/source/games/duke/src/actors_r.cpp
@@ -3533,12 +3533,12 @@ void move_r(DDukeActor *actor, int pnum, int xvel)
 			if (actor->spr.picnum == CHEER)
 			{
 				if (actor->temp_data[0] < 16)
-					actor->spr.zvel -= bcos(actor->temp_data[0] << 4) / 40;
+					actor->add_int_zvel(- bcos(actor->temp_data[0] << 4) / 40);
 			}
 			else
 			{
 				if (actor->temp_data[0] < 16)
-					actor->spr.zvel -= bcos(actor->temp_data[0] << 4, -5);
+					actor->add_int_zvel(- bcos(actor->temp_data[0] << 4, -5));
 			}
 		}
 		if (a & justjump1)
@@ -3546,12 +3546,12 @@ void move_r(DDukeActor *actor, int pnum, int xvel)
 			if (actor->spr.picnum == RABBIT)
 			{
 				if (actor->temp_data[0] < 8)
-					actor->spr.zvel -= bcos(actor->temp_data[0] << 4) / 30;
+					actor->add_int_zvel(- bcos(actor->temp_data[0] << 4) / 30);
 			}
 			else if (actor->spr.picnum == MAMA)
 			{
 				if (actor->temp_data[0] < 8)
-					actor->spr.zvel -= bcos(actor->temp_data[0] << 4) / 35;
+					actor->add_int_zvel(- bcos(actor->temp_data[0] << 4) / 35);
 			}
 		}
 		if (a & justjump2)
@@ -3559,24 +3559,24 @@ void move_r(DDukeActor *actor, int pnum, int xvel)
 			if (actor->spr.picnum == RABBIT)
 			{
 				if (actor->temp_data[0] < 8)
-					actor->spr.zvel -= bcos(actor->temp_data[0] << 4) / 24;
+					actor->add_int_zvel(- bcos(actor->temp_data[0] << 4) / 24);
 			}
 			else if (actor->spr.picnum == MAMA)
 			{
 				if (actor->temp_data[0] < 8)
-					actor->spr.zvel -= bcos(actor->temp_data[0] << 4) / 28;
+					actor->add_int_zvel(- bcos(actor->temp_data[0] << 4) / 28);
 			}
 		}
 		if (a & windang)
 		{
 			if (actor->temp_data[0] < 8)
-				actor->spr.zvel -= bcos(actor->temp_data[0] << 4) / 24;
+				actor->add_int_zvel(- bcos(actor->temp_data[0] << 4) / 24);
 		}
 	}
 	else if ((a & jumptoplayer) == jumptoplayer)
 	{
 		if (actor->temp_data[0] < 16)
-			actor->spr.zvel -= bcos(actor->temp_data[0] << 4, -5);
+			actor->add_int_zvel(- bcos(actor->temp_data[0] << 4, -5));
 	}
 
 
diff --git a/source/games/duke/src/player_d.cpp b/source/games/duke/src/player_d.cpp
index 70b989f87..10cfddde8 100644
--- a/source/games/duke/src/player_d.cpp
+++ b/source/games/duke/src/player_d.cpp
@@ -743,7 +743,7 @@ static void shootrpg(DDukeActor *actor, int p, int sx, int sy, int sz, int sa, i
 		spawned->spr.yvel = gs.numfreezebounces;
 		spawned->spr.xrepeat >>= 1;
 		spawned->spr.yrepeat >>= 1;
-		spawned->spr.zvel -= (2 << 4);
+		spawned->add_int_zvel(- (2 << 4));
 	}
 
 	if (p == -1)
diff --git a/source/games/duke/src/player_r.cpp b/source/games/duke/src/player_r.cpp
index 1d5d733b0..cc545c3e3 100644
--- a/source/games/duke/src/player_r.cpp
+++ b/source/games/duke/src/player_r.cpp
@@ -695,7 +695,7 @@ static void shootrpg(DDukeActor* actor, int p, int sx, int sy, int sz, int sa, i
 		spawned->spr.yvel = gs.numfreezebounces;
 		spawned->spr.xrepeat >>= 1;
 		spawned->spr.yrepeat >>= 1;
-		spawned->spr.zvel -= (2 << 4);
+		spawned->add_int_zvel(- (2 << 4));
 	}
 
 	if (p == -1)
diff --git a/source/games/exhumed/src/move.cpp b/source/games/exhumed/src/move.cpp
index e245cf668..4c944f3e6 100644
--- a/source/games/exhumed/src/move.cpp
+++ b/source/games/exhumed/src/move.cpp
@@ -580,14 +580,14 @@ void Gravity(DExhumedActor* pActor)
             }
             else
             {
-                pActor->spr.zvel -= 64;
+                pActor->add_int_zvel(- 64);
             }
         }
         else
         {
             if (pActor->int_zvel() > 0)
             {
-                pActor->spr.zvel -= 64;
+                pActor->add_int_zvel(- 64);
                 if (pActor->int_zvel() < 0) {
                     pActor->set_int_zvel(0);
                 }
diff --git a/source/games/exhumed/src/runlist.cpp b/source/games/exhumed/src/runlist.cpp
index 4ba5ccd04..d48071c17 100644
--- a/source/games/exhumed/src/runlist.cpp
+++ b/source/games/exhumed/src/runlist.cpp
@@ -1657,7 +1657,7 @@ int runlist_CheckRadialDamage(DExhumedActor* pActor)
 
                 pActor->spr.xvel += (edi * bcos(nAngle)) >> 3;
                 pActor->spr.yvel += (edi * bsin(nAngle)) >> 3;
-                pActor->spr.zvel -= edi * 24;
+                pActor->add_int_zvel(- edi * 24);
 
                 if (pActor->int_zvel() < -3584) {
                     pActor->set_int_zvel(-3584);