price: 5 GBP platforms: ZX81
Destroy the invading robots, or trick them into destroying themselves. Don't take too long though, or the evil Otto will be chasing you!
This game is enhanced with Chroma colour support but will also run fine on a standard ZX81 with 16K expansion.
Like the classic game, the difficulty goes up as the game progresses. However, you can set it to never go above a certain level if you like.