diff --git a/src/p_user.c b/src/p_user.c
index 9ae79e5e2..36b8eddf7 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -9989,7 +9989,7 @@ void P_PlayerAfterThink(player_t *player)
 			else if (cmd->forwardmove < 0 && player->mo->tracer->target->lastlook > player->mo->tracer->target->movecount)
 				player->mo->tracer->target->lastlook -= 2;
 
-			if (!(player->mo->tracer->target->flags & MF_SLIDEME) // Noclimb on chain parameters gives this
+			if ((player->mo->tracer->target->flags & MF_SLIDEME) // Noclimb on chain parameters gives this
 			&& !(twodlevel || player->mo->flags2 & MF2_TWOD)) // why on earth would you want to turn them in 2D mode?
 			{
 				player->mo->tracer->target->health += cmd->sidemove;