Very neat, clean, and well-thought out game! The puzzles ramped up nicely and were fun to complete, and the music and particle effects really add to the atmosphere nicely.
One thing to note is that I frequently had my key presses register as multiple, leading to the rings rotating multiple times when I meant to rotate once, and resulting in needing to start over each level multiple times. I am not sure if this is just an issue with my keyboard, but I thought I'd mention it in case it is a bug.
Great job!