Torus Trooper is an abstract shooter, created by Kenta Cho and ported to Linux by Evil Mr Henry.

Download Torus Trooper 0.22b
(0.22b is identical to 0.22, except that it fixes a linking error. If you have a working copy of 0.22, there is no need to upgrade. Also, if you have previously downloaded 0.22, replacing ttrooper with this executable will also upgrade you to 0.22b.)

Also try:
rRootage
Parsec47
A7Xpg
Tumiki Fighters
Noiz2sa