The class of vehicle that one is able to choose depends on the heaviest character selected while light characters can be paired with medium or heavy characters, they will hence be restricted to medium or heavy vehicles, respectively. The same goes for the multiple different vehicles that you're allowed to ride. Characters are separated into three different weight categories - light, medium and heavy. While overall the game is conclusively not as original as the previous installments, there is one addition that makes it unique, and that is adding two players to a vehicle, hence the name Double Dash.
The game also introduces a larger variety of karts to select from depending on the character combo's weight class rather than the standard go-kart being the sole vehicle all the racers use, and this variety of vehicles is retained in all the Mario Kart games since.
MARIO KART ISO GAMECUBE SERIES
Mario Kart: Double Dash!! is the first Mario Kart game in the series to employ 3D graphics for characters and items, as opposed to Mario Kart 64 using pre-rendered sprites to display these objects. The game is one of the few games to take advantage of LAN Mode via the Nintendo GameCube Broadband Adapter, which allows up to sixteen players to participate in a single race. In addition, the game introduces Special Items, items that are exclusive to a pair of characters, which is another feature unique to this game. The game is the only game in the franchise where two players can play cooperatively in one kart, with each player handling a single character, though the option to play in separate 2-person karts for each player is still available. Two characters handle a single kart, where one character steers and the other deals with items, and they can switch positions at any time if necessary.
MARIO KART ISO GAMECUBE DRIVER
The game, while retaining many aspects of the previous Mario Kart games, such as selecting a Mario franchise character as the player's driver and the familiar item-based weaponry that the series employs, introduces a feature that is unique to this entry in the Mario Kart series: the two-person karts, hence the title of the game. This game became popular enough to come bundled with most GameCube consoles as a starter game, like the way the red Wii is bundled with New Super Mario Bros. It was released worldwide during November 2003 and has been considered to some at the time to be the greatest in the series. Romaji: Mario Kāto: Daburu Dasshu!!) (also called MKDD, MKDD!! Double Dash, Mario Kart 4, or MK4) is a video game for the Nintendo GameCube and is the fourth main Mario Kart game in the series.