Very fun game! I loved the atmosphere and use of lighting, and collecting powerups and getting stronger was very satisfying.
Just so you know, on my first playthrough, I didn't kill the tutorial turret, went into the next room where the door shut on me, I fought the red guys, and then couldn't advance any further, I'm guessing because the turret was still alive. If possible it could be nice to make it so you can't go to the next room without killing the turret first. Great work on the game!