Nicely polished and put together. However I think the mobs should have more of an aggro range.
I didn't manage to win but I found I got my best score by just standing in the corner with my back to the wall and spamming the attack button rather than using the special abilities. But then unless they landed right in front of me, they just sat on the bottom and didn't attack. But if I tried to play "normally", the crabs just fired out and landed on my head or they bounced around and landed on my head and killed me.
I also thought there was too much camera shake, especially when it was just a tiny crab landing!