First off I have to say the level of polish on this game is just amazing, the music and sound effects fit perfectly and the use of light is great.
Some parts maybe were a bit more annoying than challenging, specifically the see-saw platform with how the controls would go out of the screen needing you to go back and controls the platform while barely being able to see it. And the part right after that with the gear on the disappearing platforms, but I did notice running and jumping into it would send it flying so I got it faster that way.
But other than that it was a fantastic game, platforming based around UI elements is such a good idea!