A wonderful piece of software.
Well, for one, it's written in LISP - and I can definitely appreciate rarities.
The graphics get an A-OK - detailed and well drawn (they remind me a bit of Amiga's Alien Breed) and the game engine works well and is really fast. The music/sound effects are good too, and the gameplay is fun.
It's very repetitive, but then it's a shooter, so what do you expect?
The Bottom Line
A rare find - a very good game written in LISP.