Sundered has a hidden skill, the roll attack, you can find in the first area below the main hub. To the right of where you acquire the cannon skill is an area that requires two end game skills to access, the hook and the wall run. In this skill gated area are endless waves of very strong enemies, and in the top right corner of the zone is an unmarked room with a corrupted treasure chest. Attack the chest enough to get the roll attack skill!