Mario & Sonic on the Wii and DS is a collection of twenty-four events based on the Olympic Games. Players can assume the role of a Nintendo or Sega character while competing against the others in these events. Players use the Wii Remote to mimic actions performed in real life sports, such as swinging a paddle. The DS version utilize the stylus and button controls. Both games closely follow rules and regulations of the specific sports. Sega adopted the IOC's mission of promoting a sporting spirit and its desire to interest young people in the Olympics by using its characters. Due to the aforementioned and the atmosphere of competitive sportsmanship the Olympics had to offer, Sega received approval by Nintendo to include Mario in the game with Sonic. Sonic the Hedgehog is the protagonist of the video game series released by Sega in order to provide the company with a mascot to rival Nintendo's flagship character Mario in the early 1990s.

Overall, critics praised the multiplayer interaction of the Wii game and variety of events of both versions. However, reviewers criticized the Wii version for its lack of simplicity and its DS counterpart for not offering the same interaction between players. The Wii title was awarded the "Best Wii game of 2007" at the Games Convention in Leipzig. Sega has sold approximately ten million units of both versions combined as of July 2008.

Gameplay

Mario & Sonic at the Olympic Games is a collection of twenty-four events based on the Olympic Games. On the Wii, the events consist of using the motion sensor capabilities of the Wii Remote and Nunchuk attachment to control the actions of the on-screen character. The player moves the remote in a manner similar to the method the separate games are played in real life; for example, swinging the Wii Remote to replicate hammer throw or pulling back the remote and tilting the Nunchuk like a bow and arrow. While the Nunchuck is required for archery, it is optional for most of the events. There are also events that are more physically demanding, such as the five running events which require rapid drumming of the controller. Some aspects of the gameplay are computer controlled. For example, in table tennis the player movement is controlled by the Wii, while the swinging of the racket is controlled by the player. The DS game is the same in design, but its events are less physically demanding than those on the Wii. For example, instead of drumming the controller, players have to quickly stroke the touchscreen.

Mario & Sonic brings together the two titular characters and fourteen more from both franchises to participate in environments based on the official venues of the 2008 Summer Olympics in Beijing. These environments are stylized to fit the futuristic and cartoon-like art styles of the Sonic and Mario franchises respectively. Each playable character has his or her own statistics which can serve as an advantage or disadvantage depending on the event. The characters are divided into four categories: all-around, speed, power, and skill. The Wii version has additional in-game characters taken from the console's Mii Channel, which allows the user to create a Mii, a customized avatar, that can be imported into games that support the feature. Both games have non-playable characters who serve as referees for particular events.