Torus Trooper
A great little 'tunnel-shooter' here, with an emphasis on speed. A LOT of speed. Think F-Zero, and multiply it by 1000. It really is insane, but in a good way. A damn good way.
Probably not a good idea to try this one if you're allergic to awesome.
Mu-Cade
I don't even know how to describe this game, other than 'Snake, on crack, heroin, copious amounts of alcohol, and god knows what else'
Stay on the platform, shooting the other 'snakes' off the platform.
Again, if you're allergic to awesome, best stay clear of this.
More games by the same people can be found here:
http://www.asahi-net.or.jp/~cs8k-cyu/index_e.html