The first time I heard the little music, I didn't know if it was because I was close to the end, or if it was the lack of oxygen driving me crazy XD I ended up dying and didn't manage to find the treasure until my third try. Which of course made me wonder: is the maze procedurally generated? It sure looks like it! So first: Wow! And second: Bravo!
As for the rest, I really liked the atmosphere. In short, a great game!