I like the art, it fits the game really well. But after a while it becomes meaningless, because it feels like it would repeat itself. Maybe it's because the levels are really big, and when I go from one Onion to the other I only see the same background over and over. The enemy's are cool, I like how they increase in Number level by level. It's also good that they sometimes get stuck in objects, so sometimes they surround me by supprise.
All in all a good game.
I don't know if it's a bug: if I put 2 fingers on the screen my player will resporn from the beginning of the level. That happened to me when I tried to click the next level. Maybe it would also help if the game would pause by getting the goal of a level