It was a bit boring the first few levels due to being able to just move the gold blocks over to where they had to be and I was about to give us when the rotating blocks appeared. This changed things quite a bit and it became alot more interesting to play.
I think this could be improved by adding the special rotating blocks and other similar features earlier in the game, probably after the first level as that allows people to get the basics of the controls without repeating another 2-3 levels before the main theme kicks in.
In short the start feels a bit slow, but once you get to the special blocks levels it becomes more challenging and interesting.