I'd like to invite this game to our contest, the Game Development World Championship! It's a simple game, but well made. I think the difficulty is about right for most players. I'd imagine this would be a fun game for two players too.
That sounds great! How do I enter? As far as a two-player version, the problem comes with having them both press a key to fire. If I kept it at 0-9, then they would have to either race to the same key or possibly have to cross hands on the same computer, which I do not think would be optimal. However, I will give it some thought.