Starter for 10 - no shooting

I wanted to make a game in which the player had to shoot headless robots to escape from a deep cavern. Today I had some of the game running without the shooting, but with around one hundred robots on screen to test the speed of Pygame as much as anything. And, much to my surprise, my wife kept wanting to play it. So already I'm not doing the game that I thought I'd be doing as there will be no shooting.