Nice work on the aesthetics and music! :D It works well, and it feels pretty satisfying to manipulate the music.
The game itself is nice. The platform physics is good to control (which isn't that easy to achieve), and the mechanics is used in some interesting ways. Not sure if the "Play" button was really necessary, I found most of the time that switching between backward and forward was enough. Globally the game is pretty easy, and consist a lot on waiting the platforms. But it's better than the other way, and as I said it's still feel good to play.
Some nitpicking I could make: switching from the keyboard to the mouse between each level isn't great, I'd rather press a key to go to the next level rather than grab my mouse to click on something. And also, no Azerty support? :P (just so you know, there's a way in unity to bind an action to a keyboard key position rather than its letter, but it's not seriously a big deal ^^)
Anyway congratulation for finishing this game. :D You even had the time to make a tutorial and a menu, which is not a small feat.