Played through two of them, don't think I'll go around and do the third. They are fun but often the riddles don't have enough there for you to make a solution, making the clue cards almost mandatory. They are almost ham-fisted with their answers or so convoluted you need to draw clue cards.
Drawing clue cards would be ok, but it goes from (You need xyz to answer this riddle) -> (have you tried obvious solution, realize that it didn't work, what weird thing could you have done to make it over) -> (if you hold the card vertically, upside down along the tick mark of the other card while balancing it over a mirror, then folding it in the shape of a dice then rolling the card three times the most probable output should be your solution)