The mechanics facilitate a great degree of tension and drama. Unique way of showing stress and exhaustion in the characters. As a GM, I would have difficulty keeping track of character secrets. Writing them down would help (and would make it easier to keep secret). Establishing relationships helps players create interesting dynamics right out of the gate.
Thanks for the feedback! Yeah, I'd have trouble keeping track of the secrets as well. In order to save on word count, I decided that I'd leave the method of tracking the secrets/relationships up to the individual GM. If they can keep it all in their head, great! If not, index-cards/text-messages/ect are also good options.