Tides of Madness adds a new twist to its super popular predecessor: Tides of Time. That twist is Madness. Some cards, while powerful, harm your psyche, so you must keep an eye on your madness level or else risk losing the game early as your mind is lost to the power of the ancients. More specifically, eight of the eighteen cards in the game feature a madness icon, and while scoring, you receive a madness token for each such icon in your collection of cards. Whoever has the most madness in a round either scores 4 points or discards 1 madness token — and the latter option is valuable because if you ever have nine or more madness, you lose the game immediately.
Don't just take our word for it! Check out this review of Tides of Madness.