All Boxed Up

You're stuck in a box, and stuff keeps flying at you. There's no way out, just see how long you can last. Grab coins while you're dodging and use them to unlock new characters, there are 10 to collect, from a ninja to an astronaut to a zombie. Pick whoever you like and get back in the box. Chase a new high score every run and chase the number 1 spot on the global leader boards. How long can you survive?