diff --git a/source/games/sw/src/actor.cpp b/source/games/sw/src/actor.cpp
index f09c61202..9e1b1d2ec 100644
--- a/source/games/sw/src/actor.cpp
+++ b/source/games/sw/src/actor.cpp
@@ -618,9 +618,9 @@ int DoActorBeginSlide(DSWActor* actor, int ang, int vel, int dec)
 {
     actor->user.Flags |= (SPR_SLIDING);
 
-    actor->user.slide_ang = ang;
-    actor->user.slide_vel = vel;
-    actor->user.slide_dec = dec;
+    actor->user._slide_ang = ang;
+    actor->user._slide_vel = vel;
+    actor->user._slide_dec = dec;
 
     //DoActorSlide(actor);
 
@@ -634,8 +634,8 @@ int DoActorSlide(DSWActor* actor)
 {
     int nx, ny;
 
-    nx = MulScale(actor->user.slide_vel, bcos(actor->user.slide_ang), 14);
-    ny = MulScale(actor->user.slide_vel, bsin(actor->user.slide_ang), 14);
+    nx = MulScale(actor->user._slide_vel, bcos(actor->user._slide_ang), 14);
+    ny = MulScale(actor->user._slide_vel, bsin(actor->user._slide_ang), 14);
 
     if (!move_actor(actor, DVector3(nx * inttoworld, ny * inttoworld, 0)))
     {
@@ -643,9 +643,9 @@ int DoActorSlide(DSWActor* actor)
         return false;
     }
 
-    actor->user.slide_vel -= actor->user.slide_dec * ACTORMOVETICS;
+    actor->user._slide_vel -= actor->user._slide_dec * ACTORMOVETICS;
 
-    if (actor->user.slide_vel < 20)
+    if (actor->user._slide_vel < 20)
     {
         actor->user.Flags &= ~(SPR_SLIDING);
     }
diff --git a/source/games/sw/src/game.h b/source/games/sw/src/game.h
index 66b443774..bc434f948 100644
--- a/source/games/sw/src/game.h
+++ b/source/games/sw/src/game.h
@@ -1040,9 +1040,9 @@ struct USER
     int  track_vel;
 
     // sliding variables - slide backwards etc
-    int16_t slide_ang;
-    int  slide_vel;
-    int16_t slide_dec;
+    int16_t _slide_ang;
+    int  _slide_vel;
+    int16_t _slide_dec;
 
     int16_t motion_blur_dist;
     int16_t motion_blur_num;
diff --git a/source/games/sw/src/player.cpp b/source/games/sw/src/player.cpp
index 176c94128..7af4aec02 100644
--- a/source/games/sw/src/player.cpp
+++ b/source/games/sw/src/player.cpp
@@ -5451,7 +5451,7 @@ void DoPlayerBeginDie(PLAYER* pp)
 
         pp->Flags |= (PF_DEAD_HEAD | PF_JUMPING);
         pp->jump_speed = -300;
-        plActor->user.slide_vel = 0;
+        plActor->user._slide_vel = 0;
         SpawnShrap(pp->actor, nullptr);
         plActor->spr.cstat |= (CSTAT_SPRITE_YCENTER);
         NewStateGroup(pp->actor, sg_PlayerHeadFly);
@@ -5484,7 +5484,7 @@ void DoPlayerBeginDie(PLAYER* pp)
 
         pp->Flags |= (PF_DEAD_HEAD | PF_JUMPING);
         pp->jump_speed = 200;
-        plActor->user.slide_vel = 800;
+        plActor->user._slide_vel = 800;
         SpawnShrap(pp->actor, nullptr);
         plActor->spr.cstat |= (CSTAT_SPRITE_YCENTER);
         NewStateGroup(pp->actor, sg_PlayerHeadFly);
@@ -5703,10 +5703,10 @@ void DoPlayerDeathCheckKick(PLAYER* pp)
             {
                 pp->KillerActor = itActor;
 
-                plActor->user.slide_ang = getangle(plActor->int_pos().X - itActor->int_pos().X, plActor->int_pos().Y - itActor->int_pos().Y);
-                plActor->user.slide_ang = NORM_ANGLE(plActor->user.slide_ang + (RANDOM_P2(128<<5)>>5) - 64);
+                plActor->user._slide_ang = getangle(plActor->int_pos().X - itActor->int_pos().X, plActor->int_pos().Y - itActor->int_pos().Y);
+                plActor->user._slide_ang = NORM_ANGLE(plActor->user._slide_ang + (RANDOM_P2(128<<5)>>5) - 64);
 
-                plActor->user.slide_vel = itActor->int_xvel() << 1;
+                plActor->user._slide_vel = itActor->int_xvel() << 1;
                 plActor->user.Flags &= ~(SPR_BOUNCE);
                 pp->jump_speed = -500;
                 NewStateGroup(pp->actor, sg_PlayerHeadFly);
@@ -5721,8 +5721,8 @@ void DoPlayerDeathCheckKick(PLAYER* pp)
     // sector stomper kick
     if (abs(pp->loz - pp->hiz) < ActorSizeZ(plActor) - 8)
     {
-        plActor->user.slide_ang = RANDOM_P2(2048);
-        plActor->user.slide_vel = 1000;
+        plActor->user._slide_ang = RANDOM_P2(2048);
+        plActor->user._slide_vel = 1000;
         plActor->user.Flags &= ~(SPR_BOUNCE);
         pp->jump_speed = -100;
         NewStateGroup(pp->actor, sg_PlayerHeadFly);
@@ -5737,8 +5737,8 @@ void DoPlayerDeathMoveHead(PLAYER* pp)
     DSWActor* plActor = pp->actor;
     int dax,day;
 
-    dax = MOVEx(plActor->user.slide_vel, plActor->user.slide_ang);
-    day = MOVEy(plActor->user.slide_vel, plActor->user.slide_ang);
+    dax = MOVEx(plActor->user._slide_vel, plActor->user._slide_ang);
+    day = MOVEy(plActor->user._slide_vel, plActor->user._slide_ang);
 
     plActor->user.coll = move_sprite(pp->actor, dax, day, 0, Z(16), Z(16), 1, synctics);
     {
@@ -5755,8 +5755,8 @@ void DoPlayerDeathMoveHead(PLAYER* pp)
 
 
             wall_ang = NORM_ANGLE(hitActor->int_ang());
-            dang = getincangle(wall_ang, plActor->user.slide_ang);
-            plActor->user.slide_ang = NORM_ANGLE(wall_ang + 1024 - dang);
+            dang = getincangle(wall_ang, plActor->user._slide_ang);
+            plActor->user._slide_ang = NORM_ANGLE(wall_ang + 1024 - dang);
 
             SpawnShrap(pp->actor, nullptr);
             break;
@@ -5765,8 +5765,8 @@ void DoPlayerDeathMoveHead(PLAYER* pp)
         {
             int wall_ang = NORM_ANGLE(getangle(plActor->user.coll.hitWall->delta())-512);
 
-            int dang = getincangle(wall_ang, plActor->user.slide_ang);
-            plActor->user.slide_ang = NORM_ANGLE(wall_ang + 1024 - dang);
+            int dang = getincangle(wall_ang, plActor->user._slide_ang);
+            plActor->user._slide_ang = NORM_ANGLE(wall_ang + 1024 - dang);
 
             SpawnShrap(pp->actor, nullptr);
             break;
@@ -5879,7 +5879,7 @@ void DoPlayerDeathBounce(PLAYER* pp)
     {
         plActor->spr.cstat &= ~(CSTAT_SPRITE_BLOCK|CSTAT_SPRITE_BLOCK_HITSCAN);
         NewStateGroup(pp->actor, sg_PlayerHead);
-        plActor->user.slide_vel = 0;
+        plActor->user._slide_vel = 0;
         plActor->user.Flags |= (SPR_BOUNCE);
 
 
@@ -5888,8 +5888,8 @@ void DoPlayerDeathBounce(PLAYER* pp)
 
     plActor->user.Flags |= (SPR_BOUNCE);
     pp->jump_speed = -300;
-    plActor->user.slide_vel >>= 2;
-    plActor->user.slide_ang = NORM_ANGLE((RANDOM_P2(64<<8)>>8) - 32);
+    plActor->user._slide_vel >>= 2;
+    plActor->user._slide_ang = NORM_ANGLE((RANDOM_P2(64<<8)>>8) - 32);
     pp->Flags |= (PF_JUMPING);
     SpawnShrap(pp->actor, nullptr);
 }
diff --git a/source/games/sw/src/save.cpp b/source/games/sw/src/save.cpp
index 1f20809c7..41447bbcc 100644
--- a/source/games/sw/src/save.cpp
+++ b/source/games/sw/src/save.cpp
@@ -815,9 +815,9 @@ FSerializer& Serialize(FSerializer& arc, const char* keyname, USER& w, USER* def
 			("point", w.point, def->point)
 			("track_dir", w.track_dir, def->track_dir)
 			("track_vel", w.track_vel, def->track_vel)
-			("slide_ang", w.slide_ang, def->slide_ang)
-			("slide_vel", w.slide_vel, def->slide_vel)
-			("slide_dec", w.slide_dec, def->slide_dec)
+			("slide_ang", w._slide_ang, def->_slide_ang)
+			("slide_vel", w._slide_vel, def->_slide_vel)
+			("slide_dec", w._slide_dec, def->_slide_dec)
 			("motion_blur_dist", w.motion_blur_dist, def->motion_blur_dist)
 			("motion_blur_num", w.motion_blur_num, def->motion_blur_num)
 			("wait_active_check", w.wait_active_check, def->wait_active_check)
diff --git a/source/games/sw/src/weapon.cpp b/source/games/sw/src/weapon.cpp
index e824cb1f3..0b9738ad6 100644
--- a/source/games/sw/src/weapon.cpp
+++ b/source/games/sw/src/weapon.cpp
@@ -5366,9 +5366,9 @@ int PlayerCheckDeath(PLAYER* pp, DSWActor* weapActor)
         DoPlayerBeginDie(pp);
 
         // for death direction
-        actor->user.slide_ang = getangle(actor->int_pos().X - weapActor->int_pos().X, actor->int_pos().Y - weapActor->int_pos().Y);
+        actor->user._slide_ang = getangle(actor->int_pos().X - weapActor->int_pos().X, actor->int_pos().Y - weapActor->int_pos().Y);
         // for death velocity
-        actor->user.slide_vel = actor->user.LastDamage * 5;
+        actor->user._slide_vel = actor->user.LastDamage * 5;
 
         return true;
     }
@@ -11114,7 +11114,7 @@ int DoSerpRing(DSWActor* actor)
     }
 
     // rotate the ring
-    actor->user.slide_ang = NORM_ANGLE(actor->user.slide_ang + actor->spr.yint);
+    actor->user._slide_ang = NORM_ANGLE(actor->user._slide_ang + actor->spr.yint);
 
     // rotate the heads
     if (actor->user.Flags & (SPR_BOUNCE))
@@ -11123,7 +11123,7 @@ int DoSerpRing(DSWActor* actor)
         actor->set_int_ang(NORM_ANGLE(actor->int_ang() - (28 * RINGMOVETICS)));
 
     // put it out there
-    actor->add_int_pos({ MulScale(int(actor->user.Dist * worldtoint), bcos(actor->user.slide_ang), 14), MulScale(int(actor->user.Dist * worldtoint), bsin(actor->user.slide_ang), 14), 0 });
+    actor->add_int_pos({ MulScale(int(actor->user.Dist * worldtoint), bcos(actor->user._slide_ang), 14), MulScale(int(actor->user.Dist * worldtoint), bsin(actor->user._slide_ang), 14), 0 });
 
     SetActor(actor, actor->spr.pos);
 
@@ -11337,7 +11337,7 @@ int InitSerpRing(DSWActor* actor)
         actorNew->user.pos.Z = 50;
 
         // ang around the serp is now slide_ang
-        actorNew->user.slide_ang = actorNew->int_ang();
+        actorNew->user._slide_ang = actorNew->int_ang();
         // randomize the head turning angle
         actorNew->set_int_ang(RANDOM_P2(2048<<5)>>5);