diff --git a/bundle/main.lua b/bundle/main.lua
index 41e2bbe..fbe2216 100644
--- a/bundle/main.lua
+++ b/bundle/main.lua
@@ -10,8 +10,7 @@ local missile_radius = 0.005
 local missile_trail_length = 7
 
 local cities = {}
-local city_width = 0.07
-local city_height = 0.05
+local city_radius = 0.05
 
 local explosions = {}
 local explosion_radius = 0.05
@@ -66,7 +65,7 @@ function spawnCities()
 	cities = {}
 	for i = 1, number_of_cities do
 		local city_x = ((i - 0.5) / number_of_cities) * (1 - 2*wall_thickness) + wall_thickness
-		local city_y = 1 - city_height/2
+		local city_y = 1
 
 		table.insert(cities, {
 			x = city_x,
@@ -141,11 +140,10 @@ function updateMissiles(dt)
 		end
 
 		for _, city in ipairs(cities) do
-			local city_left = city.x - city_width/2
-			local city_right = city.x + city_width/2
-			local city_top = city.y - city_height/2
-			local city_bottom = city.y + city_height/2
-			if city.alive and city_left <= missile.x and missile.x <= city_right and city_top <= missile.y and missile.y <= city_bottom then
+			local dx = city.x - missile.x
+			local dy = city.y - missile.y
+			local distance = math.sqrt(dx * dx + dy * dy)
+			if city.alive and distance < city_radius then
 				spawnExplosion(missile.x, missile.y)
 				-- Destroy city
 				city.alive = false
@@ -266,10 +264,9 @@ function drawCities()
 	love.graphics.setColor(1, 1, 1)
 	for _, city in ipairs(cities) do
 		if city.alive then
-			local x, y = toScreenCoordinates(city.x - city_width/2, city.y - city_height/2)
-			local width = toScreenSize(city_width)
-			local height = toScreenSize(city_height)
-			love.graphics.rectangle('fill', x, y, width, height)
+			local x, y = toScreenCoordinates(city.x, city.y)
+			local radius = toScreenSize(city_radius)
+			love.graphics.circle('fill', x, y, radius)
 		end
 	end
 end