This is an old school FPS which feels very similar to Quake. However unlike Quake this game isn't very good. I wouldn't recommend playing this unless you've played all the classic FPS already, and even then I'd just skip it.

There are too many hit scan enemies. Enemies will instantly shoot you before you can see them. The weapons are boring and ammo is scarce. Explosion collision is poor - you'll end up hitting a wall when your crosshair is clearly nowhere near one. Level design is boring. There are 3 or 4 themes with different enemy types per theme, but none of it is very memorable. The final levels are full of unfun design, such as forced pain sectors (damage from floor hazards) with limited health pick ups or enemies spawning ontop of you when collecting an item. You'll get killed by invisible traps a lot in this game. The gameplay loop is pretty much F6, die, F9, make progress, F6 ... repeat. I think there was an attempt at a story. But the final boss just ends the game.

The good parts of this game are the boss fights, they're more like mini puzzles than boss fights which is cool. You can also remove enemy limbs which stops them from being able to use their weapons. The main game takes about 3 hours to beat which means you can spend less time playing this game and play something better so that's also a plus.