The Dungeon Anarchist's Cookbook

Carl and Donut have survived so far, but this fourth level is unlike anything they could imagine. The Iron Tangle: an impossibly complicated subway system tied together into a knot of trains of all kinds. The top ten list of most popular crawlers is now confirmed, and Carl and Donut have made it. But that popularity comes with a price... They each now have a bounty on their head. To get to through this level, they must solve the puzzle of the floor. The secret to unravelling it all may be hidden in the pages of a seemingly useless book.