The number of rooms and how similar they look makes it easy to get lost. The time you're given to explore doesn't seem like enough given how many rooms there are, either. I tried a bunch of times but was only able to get the square key.
The lack of a true fullscreen meant my cursor kept going outside of the game, which got annoying.
I really like the textures of the walls and doors. They make good use of the black and white art style.