I was always partial to Alien Bash 2.
This was/is an excellent game! No doubt the best free game ever. I still have a copy that sees much use.
Others along this line, such as Chaos Engine are also damn good.
It's almost like the Amiga was a test bed for gaming ideas. Who would ever have thought It came from the Desert (or other Cinemaware titles) would have caught on. They are odd games to say the least - but excellent!
It's frustrating how hard it is to find some old Amiga games.