Really enjoyed the size changing mechanic on this one and  getting to break things with it!  By the end of the 3 levels, the doors and minecarts were starting to lose their uniqueness as gimmicks, so I think it was good to stop there.  Would've liked to have seen more levels with additional elements to play with, though!

Roughly beat them in 40s, 50s, and 65s :)

I wish the music looped a little better.  Felt a little abrupt whenever it ended.