Gosh, this game was so much fun! I wouldn't have thought to use the mechanic you did in this way, but it really works well! Took a bit for me to figure out what to do, admittedly. However, once I did, it was great! Awesome graphics and the music really suits too.
One criticism would be to have the Retry button appear when you die. Cause I had to refresh my browser in order to restart the game. Otherwise, great job!