Intense Difficulty:
Beat the story mode on hard difficulty.

Taunting:
Press L during play to hear your character's taunt. You can only do this while on the game board, not in mini-games. Press L + C-stick Up for a faster version or L + C-stick Down for a slower version. Press L + C-stick Left or C-stick Right to change the volume

Bowser's Nightmare:
Beat Bowser's board in Story mode to unlock it in Party mode.

Thanks to Revolution readers Dallas, Bahamut, and Supabad!