Shameless plug
Amiga FPS!
http://www.youtube.com/watch?v=2Qd4BW4nNI0Anyway on to Breathless, i remember a moment when you when down this massive lift and bads guys are shooting at you all over the place, it was a good game.
But for me the best first person shooter on the Amiga had to be Alien Breed, just the sound of the shotgun going off and then the next thing your here was a scream and splat. A great game shame it didn't have 1x1 pixels option. The squeal was just not as good, but technically impressive.
I remember when I went to the shops to get my first doom clone game on the Amiga and there was Alien Breed 3d, Gloom or Fears, I stupidly picked Fears only because it said it had a level editor in it, which it did and was more fun making 3d levels in that then playing the game.
However I must say who ever coded Fears must of been pretty good, full screen on a standard A1200 and not that bad speed.
PS: Genetic Species not running quick enough on 060 with RTS, I find that hard to believe, it run well on my amiga with just aga and 040.