Enjoyed the game. Had quite a fun retro feel to the aesthetics, and the music really fit. Couldn't get past level three though, lol. The difficulty kinda ramped up at that point, at least for me =P
Yes, I've been told about the difficulty curve being too high on level 3. I'll fix that in a future version with more levels to gradually increase difficulty. The good thing is you can skip to a different level at any time through the pause menu. :)