Hidden Characters
"Mario Kart: Double Dash!!" offers 16 characters to choose from at the start of the game. You can unlock the lightweight duo of Toad and Toadette by earning first place in the Special Cup at 100cc. After you complete the Star Cup in Mirror Mode, King Boo and Petey Piranha, two additional heavyweight characters, are available for use.
Extra Karts
The game features 13 hidden karts that appear as you complete the game's cups under different difficulty levels. For example, the Green Fire Kart is available after you win the Mushroom Cup in the 50cc class, the Waluigi Racer Kart is available after you complete the Flower Cup in the 100cc class and the Barrel Train Kart appears after you win the Star Cup in the 150cc class.
Extra Cups
The Special Cup, which leads players through Wario Coliseum, Dino Dino Jungle, Bowser's Castle and Rainbow Road, becomes available after you complete the Star Cup in the 100cc class. If you can complete this new cup in the 150cc class, you will unlock yet another challenge. The All Cup Tour challenges you to complete every course in the game in a random order. Complete the All Cup Tour in the 150cc class to access Mirror Mode, which allows you to player each course in reverse.
Battle Mode Stages
Battle Mode initially offers four stages: Cookie Land, Block City, Nintendo GameCube and Pipe Plaza. Complete the Mushroom Cup in the 150cc class to unlock Luigi's Mansion, a three-story arena based on a game of the same name. Finish the Flower Cup in Mirror Mode to access Tilt-a-Kart, a course in the shape of giant pixilated Mario figure from "Super Mario Bros."