Has a few interesting setups, but overall doesn't do much for me. I can see other people enjoying it, though.
The message box in the second level confused me - I figured it meant that I had to kill every enemy in the level to beat it, but it just turned out to be advice. Killing every enemy usually doesn't even help that much, just saying.
The castle with the moving blocks was an odd difficulty spike.
Also, next time, please add a proper End of Demo level.