Found an interesting bug while trying to look for one of the endings not in a playthrough on YouTube. If you leave the cabin after unlocking the cellar hatch but before going inside, you'll be taken to a glitchy version of the cabin with segmented rooms and invisible walls. There doesn't seem to be any escape, and you just walk over the cellar hatch. I guess this can be prevented by having your friend go "Hey! We just opened this thing, there's no leaving just yet!" and stopping you.
Unless, of course, this IS one of the endings, haha.