Porting multi-z support updates.

code/modules/mob/living/living.dm

@@ -40,6 +40,16 @@
 	QDEL_LIST(diseases)
 	return ..()
 
+/mob/living/onZImpact(turf/T, levels)
+	if(!isgroundlessturf(T))
+		ZImpactDamage(T, levels)
+	return ..()
+
+/mob/living/proc/ZImpactDamage(turf/T, levels)
+	visible_message("<span class='danger'>[src] crashes into [T] with a sickening noise!</span>")
+	adjustBruteLoss((levels * 5) ** 1.5)
+	Knockdown(levels * 50)
+
 /mob/living/proc/OpenCraftingMenu()
 	return
 

code/modules/mob/living/living_movement.dm

@@ -32,4 +32,7 @@
 		if(drag_slowdown && L.lying && !L.buckled && grab_state < GRAB_AGGRESSIVE)
 			add_movespeed_modifier(MOVESPEED_ID_PRONE_DRAGGING, multiplicative_slowdown = PULL_PRONE_SLOWDOWN)
 			return
-	remove_movespeed_modifier(MOVESPEED_ID_PRONE_DRAGGING)
+	remove_movespeed_modifier(MOVESPEED_ID_PRONE_DRAGGING)
+
+/mob/living/canZMove(dir, turf/target)
+	return can_zTravel(target, dir) && (movement_type & FLYING)