I very much enjoyed the game, sadly it broke for me though;
Also perhaps something to change would be the pause it does after you hit a red valve. If you're going to force players to fall to a certain spot, I don't think you need that pause in there. Just bounce 'em back and let them fall to the spot you want them to.
The reason for this being; If you're supposed to rotate during pause, but you can't do it there, it feels inconsistent.
And second reason it's an inconsistency that feels like a needless hassle that can just be taken out. Or at least in the final version :D
Aside from that some small points. The contrast at the start was hard for me to see. And perhaps add a smoother rotation. It's a nicety that shows some polish and is of course very pleasing to the eye.
All in all, a solid entry and nice game. Keep it up!