I had a blast playing this. Highly addictive (almost too much so, I have work to be getting on with :) )
The idea is really well presented, and you explain how to play so minimally, and it all just clicks.
I died on the last stage of my first run due to a mistimed move, and completed the second run then.
Awesome array of enemies, even for 10 levels.
The fact that the powerups only last a level made me just prioritize health on the second run as if I had selected that extra heart on run 1, I would have completed it on run 1.
I could see myself losing hours to this. Great that there is a story mode there for players interested in that. In a game like this, I would be keen to just blast out levels.
Would highly recommend this to anyone that comes across the page. It made me feel about 15 years younger, and I've left thinking I have the reflexes of a Hawk and that theres fight in the old dog yet ;)
Awesome job.