diff --git a/game/render.odin b/game/render.odin
index 708e026..92c00e9 100644
--- a/game/render.odin
+++ b/game/render.odin
@@ -4,6 +4,7 @@ render_world :: proc(world: ^World) {
 	render_map(world)
 	render_enemies(world)
 	render_towers(world)
+	render_placement_preview(world)
 	render_projectiles(world)
 }
 
diff --git a/game/tower.odin b/game/tower.odin
index ada77dc..5b86c2f 100644
--- a/game/tower.odin
+++ b/game/tower.odin
@@ -56,6 +56,15 @@ TOWER_ARCHETYPES: [Tower_Kind]Tower_Archetype = {
 	},
 }
 
+can_place_tower :: proc(world: ^World, gx, gy: int, kind: Tower_Kind) -> bool {
+	if world.phase != .Build do return false
+	arch := get_archetype(kind)
+	if world.gold < arch.cost do return false
+	if !footprint_fits_map(&world.world_map, gx, gy, arch.footprint_w, arch.footprint_h) do return false
+	if footprint_blocked(world, gx, gy, arch.footprint_w, arch.footprint_h) do return false
+	return true
+}
+
 rects_overlap :: proc(
 	left_a, top_a, width_a, height_a: int,
 	left_b, top_b, width_b, height_b: int,
@@ -80,9 +89,11 @@ footprint_fits_map :: proc(world_map: ^Map, gx, gy, footprint_w, footprint_h: in
 	if gx + footprint_w > MAP_W do return false
 	if gy + footprint_h > MAP_H do return false
 
-	for row in gy ..< gy + footprint_h {
-		for column in gx ..< gx + footprint_w {
-			if !can_build_at(world_map, column, row) do return false
+	for column in gy ..< footprint_h {
+		for row in gx ..< footprint_w {
+			cell_column := gx + column
+			cell_row := gy + row
+			if !can_build_at(world_map, cell_column, cell_row) do return false
 		}
 	}
 
@@ -114,21 +125,14 @@ get_archetype :: proc(kind: Tower_Kind) -> Tower_Archetype {
 }
 
 try_place_tower :: proc(world: ^World, gx, gy: int, kind: Tower_Kind) -> bool {
-	if world.phase != .Build do return false
+	if !can_place_tower(world, gx, gy, kind) do return false
 
 	arch := get_archetype(kind)
-	footprint_w := arch.footprint_w
-	footprint_h := arch.footprint_h
-
-	if !footprint_fits_map(&world.world_map, gx, gy, footprint_w, footprint_h) do return false
-	if footprint_blocked(world, gx, gy, footprint_w, footprint_h) do return false
-	if world.gold < arch.cost do return false
-
 	world.gold -= arch.cost
 	append(
 		&world.towers,
 		Tower {
-			position = footprint_center(gx, gy, footprint_w, footprint_h),
+			position = footprint_center(gx, gy, arch.footprint_w, arch.footprint_h),
 			anchor_gx = gx,
 			anchor_gy = gy,
 			kind = kind,
@@ -223,3 +227,26 @@ render_towers :: proc(world: ^World) {
 	}
 }
 
+render_placement_preview :: proc(world: ^World) {
+	if world.phase != .Build do return
+
+	mouse := game_mouse()
+	gx, gy := screen_to_grid(mouse.x, mouse.y)
+	arch := get_archetype(world.selected_tower)
+	ok := can_place_tower(world, gx, gy, world.selected_tower)
+
+	center := footprint_center(gx, gy, arch.footprint_w, arch.footprint_h)
+	rl.DrawCircleLines(i32(center.x), i32(center.y), arch.range, rl.Fade(rl.SKYBLUE, 0.4))
+
+	tint := rl.Fade(rl.GREEN, 0.3)
+	if !ok do tint = rl.Fade(rl.RED, 0.35)
+
+	for row in 0 ..< arch.footprint_h {
+		for col in 0 ..< arch.footprint_w {
+			px := (gx + col) * TILE_SIZE
+			py := (gy + row) * TILE_SIZE
+			rl.DrawRectangle(i32(px), i32(py), TILE_SIZE, TILE_SIZE, tint)
+		}
+	}
+}
+