Thanks for playing~ i managed to beat it with 16 gems remaining. but with faster undo (and the fast travel trick) i can do 43 - ah yes, some of the secret walls are unintentional - i couldve changed the tile to a different color to test it beforehand (the intentional ones are: room 0 right door was intentional as that get you to the "black" key, one connecting between room 0 (left) to room 2 and one on room 4 to get to the black tile)