How do you win the Undefined challenge (#12)? ;)
For anyone having a hard time with the last few levels: If you commit suicide by jumping off the edge of the map, it counts as a death and you get full health--but it doesn't count as a kill for the other guys and they don't get a point for it.
On level 39, whenever I try to put the boxes in the portal at a critical part, they disappear and respawn down below, making it impossible to beat the level >:(