Nightmare Castle

You have woken up in a dark, small, empty dungeon, with only your own light to see with. How did you get there? More importantly, how will you get out? It's not as simple as just walking out the door, because on the other side of that door lies an entire labyrinth of a castle, where the laws of physics simply do not apply. Interact with everything you see to find as many keys as you can, so that you can unlock as many doors as you can! One of these doors has to be the way out, right? But beware, for while the castle seems empty, there is some sort of presence lingering over you, closing in on you with each passing second! Maybe there are things in this castle that you aren't meant to see...