Move your mouse or hold tap where you want to shoot. Enemy spawn rates slowly increase while playing. Killing an enemy rewards you with 2 points each. The purple plus button allows you to upgrade pieces, upgrading a piece turns it into a turret, upgrading costs 10 points. the red trash button allows you to sell pieces for 10 points each.
Made this in a couple days around the theme "Limited Space", simple project, hope you enjoy it.