Orcs Must Die! 2 - The Skull Collector Challenge <br /> <br />Tackling the hardest map of all, The Hive, from the Are We There Yeti? DLC, with no skull spent : no upgrades, and only the items unlocked through gameplay. <br /> <br />Check out the Challenge topic on the offical forums : <br />http://forums.robotentertainment.com/showthread.php?41-The-Skull-Collector-Challenge
