The graphics of the game and the sound effects are awesome! The sound makes it a kinda spooky atmosphere. I found a few thingss that could be fixed: 1. you can't climb up this ladders a second time, 2. this "E" box thats shown when you are next to a keycard also shows when the enemy touches it, 3. if you are dead and haven't used Shift to rewind yet you can still use Right Mouse Button.
But that doesn't really really interfere with the gameplay and your game is really fun to play :)