Useful but not really needed to play. Each card explains the featured power without the page flipping of the rule book. Makes keeping track of powers as easy as handing out a card.
This game is a nice change from the break down the door and kill them all games that are out now. I played the 0-level adventure at a local comic shop on free RPG day and had a blast. The character funnel is fun. You start with three peasant characters and hope that one survives to become a first level adventurer. The book also contains a fifth level adventure that looked very short. I never got to play it. Great art! If you like old school you should get this book for the art alone.