Shame that there isn't no audio, as Horror games can really benefit from them.
Still, it's a good presentation of a concept, and the feel of the game in controls and looks is already there.
There is one entire room where the walls just don't work, and the door to get to the key didn't want to let me through at the beginning. You already mention this is a prototype tho, so right now it's fine. Just make sure to check those colliders when making a bigger game!