The idea is pretty cool, though it is pretty repetitive. I like the banging on the door, it is pretty cool. I know it may seem like a good idea to give the user options that you have at the beginning, but I honestly think it takes away from the experience a little bit. Makes it feel less like a game and more like a simulation almost, if that makes any sense. What you could do is instead just do like an Easy, Medium, and Hard mode that has three predetermined settings. It's a small thing but I figured I would share. Still though, great job :)