Phantom Slayer is a simple but fun maze/exploration game, based on the original game for the TRS80 Color Computer.
You explore a 3D maze, attempting to kill off the phantoms in the maze. You get an audible clue when phantoms are nearby, rapid heavy breathing. Your gun has a two second recharge time, and there is also a teleport in the maze which takes you back to your start.
You can have either modern or retro graphics.
This game is now nearly thirty years old, but the original was notoriously creepy. I think Ive managed to get some of the original creepiness in the game.
This game is free as in really free, it is open source, there are no adverts, nothing you can buy, sell or rent, no extra levels. Its just there for a bit of fun if you want. Or not if you dont.