This is a very nice little puzzle platformer! I really like how carefully the levels are constructed to start out simple but sloly ramp up the challenge. The mechanic is simple but interesting, I can see a lot of potential in it. 

That bit of text is also very intriguing. It's a pity the game has only 4 levels, I would love to play more of it. Both because it's fun and because I want to know what's next in the story :D

The only thing is that sometimes movement seems a bit "choppy" to me, as if there is a constant friction against the ground. Maybe something up with physics material?

Overall, good job on the game!