Overall the design is really good. It reminds me of the game "Quell".

The gameplay is very fluid and I can picture it working really well with swipe gestures on a touchscreen. The feeling of velocity and impact of the moves is nicely done.

Regarding difficulty, I found it to be a very smooth, easy progression at first and then the difficulty kicked in at level 14.

Too hard? I don't know. It depends on the audience you are going for. I think the casual market probably wants a *very* gradual increase in difficulty (if any...) while others will appreciate the challenge.

I really liked the progress bar at the top showing the moves so far and the goals.

I love the look and feel of the game. Some initial impressions:

 - Brutal difficulty. I'm fine with that, but maybe ease up at bit at first.

 - Bizarre controls. This is both a good and bad thing. I was initially completely perplexed and frustrated when playing anything but the controller. Once I figured it out, the controls were fun, but I shouldn't have had to go through the frustration (many people will just quit).

 - "Waggle" to select for the controller is more than just unintuitive. I got to the power-up screen multiple times and quit the game because I couldn't do anything. Just use the main button to select like the player expects.

Everything else about the game screams awesomeness. Just get rid of the barriers to a person figuring out how to play it.

Congrats on the release!

I just played through all of the work-in-progress builds and it was interesting to see how it improved over time. Love the aesthetic of the game.