I can't believe this only got Daily 5th page, when it's one of the best hack n' slash games on NG. Great music, plenty of levels and enemy types, a great sense of humor, and CO-OP. The gameplay is also simple but varied in its own way.
The only suggestions I have for improvement would be letting us advanced to the next level by pressing a keyboard button rather then having to click it. Possibly if this game gets a sequel, having multiple paths to go rather then a straight line down the map. Finally, an arena mode where you survive waves of enemies could be a fun distraction. It could also have simple mini games, such as one where you have to throw bottles to hit targets.