There isn't much to this, but all the controls function as intended so it gets a bare pass. The battery life is long enough to have no concerns with lasting the night, and it's good programming to have it as it's own resource stat. Staring at the same green wall and two door frames for 3 minutes got bland quickly, maybe try something decorating the wall. As a way to distract the user from focusing, maybe have little effects or something pop up now and then to draw the eye away from the threat area.
Sound wise, the creaky door got monotonous and didn't quite have the ominous feel it should. Maybe a variety of sounds: squeaking floorboard, door, ghostly wind.
You have all the functional basics here, next thing is to take it a step further to really involve the user.