The first game to feature Mario and Diddy Kong together. Diddy Kong was originally owned by Rare, who produced the Donkey Kong Country (1994) series. In those games, the Rare logo is visible on Diddy Kong's cap. Nintendo bought the rights to the character, and he appeared in this game. The Rare logo is now a Nintendo logo.
The game has two different versions of Bowser Jr. unlockable - his normal form and Shadow Mario (Shadow Mario is Bowser Jr. from Super Mario Sunshine, in a Mario disguise.) Reissued as a "greatest hits" title.