You captured the horror atmosphere perfectly - great sound design, and use of lighting. The mechanics fit the theme well, and I know how difficult it is to fill 3d environments with so much stuff in a short time frame.
It's been said a few times in other people's comments, so I won't complain about the walk speed, but I think my only other major gripe is that it's kind of hard to navigate in the forest. There's a lot of area to cover, with a lot of trees, but then all of the keys are in the one area that's different. It might be worth making the trees a little more sparse and/or clumped, and having a few other points of interest dotted around. Considering the amount of environmental work you'd already done, it would have been a lot to expect, but it's something to bear in mind in the future, or if you're planning to update the game once the judging period is over.