Awesome game! Really neat idea to bounce along the edges of the box. I made it to the fourth stage and got killed by a bunch of dumb lizards. I thought the upgrade system was really well implemented and the enemies really kept me on my toes. I think my only complaint would be the aforementioned lizards since they can come out of nowhere without any warning. Originally it seemed like I only had to avoid them on the bottom, but they came out of the top too later on. I also got ambushed by some bats when I was on the top since they spawn above you. Also, getting sent back to the beginning can be pretty punishing, especially since the first part is pretty boring. Would have loved to have kept going from my current level, but I understand that probably wouldn't have worked entirely with your chosen upgrade system. Great job!