New Super Mario Bros. Wii is a platformer that continues the story of Mario and his friends. Princess Peach has been kidnapped again, and it's up to Mario, Luigi, and two Toads to rescue her once more. The journey begins with Bowser Jr. and the seven Koopalings stealing the birthday cake, which sets off the chaos.
The gameplay is similar to previous Mario games, with players jumping, dashing, and grabbing power-ups like the Super Mushroom and Fire Flower. New power-ups have been added, such as the Propeller Hat, Ice Flower, and Penguin Suit, which provide new abilities for players. Yoshi returns as well, allowing players to ride him and eat enemies and berries in levels.
The Wii Remote's tilting feature is used in creative ways throughout the game. Players can use it to activate certain parts of levels, such as jumping onto specific platforms or aiming a light on a boat. Shaking the Wii Remote while wearing the Propeller Hat causes the player to fly straight up, and shaking it near objects picks them up or throws them.
The game features a "Super Guide" mode, which allows players to progress through the game even if they're struggling with difficult levels. When a player dies eight times in total in a level, Luigi will take over and play through the level, showing them how to complete it.
One of the unique features of New Super Mario Bros. Wii is its multiplayer mode. Up to four players can play simultaneously, with the option to keep returning to the game even after dying by floating in a bubble. Another mode, Coin Battle, has all players competing against each other to pick up the most coins.