This thing is pretty intense. I had heard about it a while ago, but never tried it until today. WOW. There are some intense effects going on. Apparently, it’s a procedural engine, so everything in the game is generated based on a script; no textures or geometry is stored. But it looks wonderful! And 96kb? Why not!!
http://www.theprodukkt.com/kkrieger.html
(and there are more guns than that, but those are just 2 shots)