Interesting concept but could be taken further
I liked the concept, but it looked to me like more of a programming exercise than a fun game. On the concept of shifting, that's something I think you've got there, if you develop it more. As a whole game, it isn't that fulfilling. If you want to focus on the puzzle element, I think it's too easy. It's not a normal platformer/action game either, so I think adding elements where you have to jump over spikes seemed a bit out of place. Perhaps in future iterations (I've not played Shift 2 yet) you could have a puzzle set and an action set, where the puzzles are harder in the first and there's more action in the latter.
So, it looks more like something you'd make as a demo of what you could do in flash than a game that's fun to play.