It's a great game, I just have a few suggestions:
- There needs to be a controls list somewhere in the game (best in the pause menu, since it opens with the traditional Esc key), maybe even hints to the controls. I had to go back to this page twice to read the controls, first to figure out how to open doors and then how to shoot.
- Six shots to kill an enemy is too much. 3 or 4 would be better.
- It would be good to have an aim tutorial or at least have the game make the player take out the gun and shoot something (e.g. a lock) before facing the first enemy.