Bloodwar: A Doom Engine Sci-Fi FPS
This is a Doom engine FPS game called Bloodwar, which was made by Audom Moy, who is known for the Angry Anna Doom WAD series. This game uses GZDoom, as a copy of the source port is included with the game. The premise of this FPS game is that a retired scientist who is abducted by aliens, and must escape their spaceship. The weapons you find and use don't use ammo, but instead use your own blood, which takes away health. The good news is that the aliens drop hearts and medikits after death, which gives you health. The concept of this game is really cool, and even though this game has some issues, it's still fun to play.
Go here to get the game Bloodwar:
https://audom-moy.itch.io/bloodwar