SDLRoids is essentially an Asteroids clone, but with a few extra
features, and some nice game physics. It is based on xhyperoid, which
is a UNIX port of the 16-bit Windows game Hyperoid. Major changes from
xhyperoid are that it's using SDL for sound and graphics, has a couple
of extra powerups  and that the shield behaves differently.

WWW: http://david.hedbor.org/projects/sdlroids/