This design is so elegant! The concept is really well thought, and served with some amazing juiciness! It just provides incredible sensation.
I thought I would be forever stuck on the last level (triangle), but eventually achieved to beat it with the bonus attack. The game becomes quickly difficult, which I guess is by choice. And most of the time the challenge is actually really satisfying! However, it comes with some frustration too. Many time I had the impression that I failed not because I didn't reacted fast enough (although it did also happen), but because I took a bad decisions 1 or 2 seconds ago that brought me in a situation where I couldn't win. And this didn't feel really great. There are even some obstacles that I couldn't find how to reasonably avoid, other than with cheer luck (mostly when it involved aiming missiles, or too many "rockets" coming from the center with no readable order).
Still I enjoyed completing it, and playing with the two alternative controls! It's an intense and unforgivable game, but that can quickly become addictive. I found displaying the remaining health on defeat is a clever choice, often giving a little hint that beating the level might be actually reachable. This demo was already quite fun, i'm curious to see the final game!