Originally this is only part of a larger custom level in the game "Wonderland". The Wonderland version is only 6x6, what you see here is my (not particularly successful, apparently) attempt at adapting it in CC. To better imitate the level as it works in Wonderland, you could try this: don't enter any room more than once (a room is a region with 5 dirt tiles in a "+" shape, plus the surrounding "ring" with the 4 popup walls). Also pretend that there's a popup wall buried underneath each block.