Truth.

code/game/atoms.dm

@@ -516,7 +516,7 @@ var/list/blood_splatter_icons = list()
 		germ_level = 0
 		if(islist(blood_DNA))
 			blood_DNA = null
-			return 1
+			return TRUE
 
 
 /obj/item/clean_blood()

code/modules/projectiles/projectile.dm

@@ -121,10 +121,10 @@
 	var/turf/step_cardinal = !(splatter_dir in list(NORTH, SOUTH, EAST, WEST)) ? get_step(target_loca, get_cardinal_dir(target_loca, step_over)) : null
 
 	if(step_over.density && !step_over.CanPass(target, step_over, 1)) //Preliminary simple check.
-		return 1
+		return TRUE
 	for(var/atom/movable/border_obstacle in step_over) //Check to see if we're blocked by a (non-full) window or some such. Do deeper investigation if we're splattering blood diagonally.
 		if(border_obstacle.flags&ON_BORDER && get_dir(step_cardinal ? step_cardinal : target_loca, step_over) ==  turn(border_obstacle.dir, 180))
-			return 1
+			return TRUE
 
 /obj/item/projectile/proc/vol_by_damage()
 	if(damage)