Orcs Must Die! 2 - The Skull Collector Challenge
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.
Check out the Challenge topic on the offical forums :
http://forums.robotentertainment.com/showthread.php?41-The-Skull-Collector-Challenge
