Falling onto stairs from height, or falling onto obstacles, causes damage.

code/modules/lighting/lighting_overlay.dm

@@ -146,7 +146,7 @@
 	SHOULD_CALL_PARENT(FALSE)
 	return
 
-/atom/movable/lighting_overlay/can_fall()
+/atom/movable/lighting_overlay/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	return FALSE
 
 // Override here to prevent things accidentally moving around overlays.

code/modules/mechs/mech_movement.dm

@@ -25,9 +25,9 @@
 		return ..(dir)
 	return ..(ndir)
 
-/mob/living/exosuit/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = src.loc)
+/mob/living/exosuit/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	//mechs are always anchored, so falling should always ignore it
-	if(..(TRUE, location_override))
+	if((. = ..(TRUE, location_override)))
 		return !(can_overcome_gravity())
 
 //For swimming

code/modules/mob/living/living.dm

@@ -1174,13 +1174,14 @@ default behaviour is:
 		client.screen += hud_used.hide_actions_toggle
 
 /mob/living/handle_fall_effect(var/turf/landing)
-	..()
-	if(istype(landing) && !landing.is_open())
-		apply_fall_damage(landing)
-		if(client)
-			var/area/A = get_area(landing)
-			if(A)
-				A.alert_on_fall(src)
+	if(!(. = ..()) || !istype(landing))
+		return
+	apply_fall_damage(landing)
+	if(!client)
+		return
+	var/area/landing_area = get_area(landing)
+	if(landing_area)
+		landing_area.alert_on_fall(src)
 
 /mob/living/proc/apply_fall_damage(var/turf/landing)
 	take_damage(rand(max(1, ceil(mob_size * 0.33)), max(1, ceil(mob_size * 0.66))) * get_fall_height())

code/modules/mob/living/silicon/robot/flying/flying.dm

@@ -46,7 +46,7 @@
 /mob/living/silicon/robot/flying/Process_Spacemove()
 	return (pass_flags & PASS_FLAG_TABLE) || ..()
 
-/mob/living/silicon/robot/flying/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
+/mob/living/silicon/robot/flying/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	return !Process_Spacemove()
 
 /mob/living/silicon/robot/flying/can_overcome_gravity()

code/modules/multiz/movement.dm

@@ -111,7 +111,7 @@
 		moving = FALSE
 
 //For children to override
-/atom/movable/proc/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
+/atom/movable/proc/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	if(immune_to_floor_hazards())
 		return FALSE
 
@@ -137,16 +137,16 @@
 
 	return TRUE
 
-/obj/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
-	return ..(anchor_fall)
+/obj/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
+	return ..(anchor_fall, location_override)
 
-/obj/effect/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
+/obj/effect/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	return FALSE
 
-/obj/effect/decal/cleanable/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
+/obj/effect/decal/cleanable/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	return TRUE
 
-/obj/item/pipe/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
+/obj/item/pipe/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	var/turf/open/below = loc
 	below = below.below
 
@@ -158,18 +158,21 @@
 	if((locate(/obj/structure/disposalpipe/up) in below) || locate(/obj/machinery/atmospherics/pipe/zpipe/up) in below)
 		return FALSE
 
-/mob/living/can_fall(var/anchor_bypass = FALSE, var/turf/location_override = loc)
+/mob/living/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	if((. = ..()))
 		var/decl/species/my_species = get_species()
 		if(my_species)
 			return my_species.can_fall(src)
 
 /atom/movable/proc/protected_from_fall_damage(var/turf/landing)
-	if(!!(locate(/obj/structure/stairs) in landing))
-		return TRUE
-	var/turf/wall/natural/ramp = landing
-	if(istype(ramp) && ramp.ramp_slope_direction) // walking down a ramp
-		return TRUE
+	// Stairs and ramps will not save you from a high drop.
+	if(get_fall_height() <= 1)
+		if(!!(locate(/obj/structure/stairs) in landing))
+			return TRUE
+		var/turf/wall/natural/ramp = landing
+		if(istype(ramp) && ramp.ramp_slope_direction) // walking down a ramp
+			return TRUE
+	return FALSE
 
 /mob/protected_from_fall_damage(var/turf/landing)
 	. = ..()
@@ -213,10 +216,16 @@
 
 /atom/movable/proc/handle_fall_effect(var/turf/landing)
 	SHOULD_CALL_PARENT(TRUE)
-	if(istype(landing) && landing.is_open())
-		visible_message("\The [src] falls through \the [landing]!", "You hear a whoosh of displaced air.")
+	if(istype(landing) && can_fall() && landing.CanZPass(src, DOWN))
+		visible_message(
+			SPAN_NOTICE("\The [src] falls through \the [landing]!"),
+			"You hear a whoosh of displaced air."
+		)
 	else
-		visible_message("\The [src] slams into \the [landing]!", "You hear something slam into the [global.using_map.ground_noun].")
+		visible_message(
+			SPAN_DANGER("\The [src] slams into [landing.is_open() ? "\the [landing]" : "an obstacle"]!"),
+			"You hear something slam into the [global.using_map.ground_noun]."
+		)
 		var/fall_damage = fall_damage() * get_fall_height()
 		if(fall_damage > 0)
 			for(var/mob/living/M in landing.contents)
@@ -421,7 +430,7 @@
 	owner = null
 	. = ..()
 
-/atom/movable/z_observer/can_fall()
+/atom/movable/z_observer/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	return FALSE
 
 /atom/movable/z_observer/explosion_act()

code/modules/multiz/zmimic/mimic_movable.dm

@@ -49,7 +49,7 @@
 	mouse_opacity = FALSE
 	abstract_type = /atom/movable/openspace // unsure if this is valid, check with Lohi -- Yes, it's valid.
 
-/atom/movable/openspace/can_fall()
+/atom/movable/openspace/can_fall(anchor_bypass = FALSE, turf/location_override = loc)
 	return FALSE
 
 // No blowing up abstract objects.