I have a few, though 2 may be the same game.
1.
A 3D PC FPS game
I recall playing it on an old Windows 95-98 machine. While I can't say for sure,
it was probably around 2000-2003 when I played it, but I recall it looking like something
akin to Quake.
Some telling things I remember...
Spawn with a pistol
Spawning inside a small outdoor enclosure ( fenced in? ) with an entrance into
a building nearby. The outside area was a bit drab and gray. Entering through the door,
there was a fairly well-lit hall ( yellow/white lighting? ) with what I recall having RED carpet, and a guard or two closed in and shot at you.
Shooting the guards in specific body parts caused said parts to come off, but they didn't
seem to phased by it and would continue to shoot at you. There was definitely blood.
The game had a fairly gritty feeling to it. The closest thing I can find is soldier of fortune... but it just doesn't seem like the right fit. The enemies/guards seemed less human in my memory. Almost like mindless zombie guards, haha
2.
I don't know if this is the same game as above... it doesn't make sense but I recall it
being the case.
The only thing I remember about it is the title screen and that it was full 3D.
The main menu selection available as you would see in DOOM or Quake, with a stream of gameplay
rolling in the background. But I specifically remember this background being a camera panning through
a level. Not the POV of a player like in DOOM or Quake. And one of the enemies that can be seen
is an evil ass fucking clown with sawblades.
3.
A 3D PS1 FPS game.
The disk art's color pallet was primarily blue/gray, and there was a spaceship
of sorts flying front facing in the foreground.
In the game, you hover around in your spaceship on streets, shooting at enemies.