You let your cursor hover over an enemy and they will die and disappear. If they reach the black line on the bottom you lose 1 health. I didn't give you 200 lives for no reason. This game is REALLY HARD. BETTER PLAYED SMALL SCREEN. 100% permission to remix or use scripts/sprites/costumes/backdrops. DO NOT USE TURBO MODE. The clones will automatically delete because turbo mode works by making all the blocks run at once.
Your hand holding the mouse may wobble and twitch wildly during the game. THIS IS NATURAL. I got the idea when I found out the google easter egg for zerg rush.