Mario Kart 64 is a racing game that is part of the Mario Kart series, originally released for the Nintendo 64 in 1996 in Japan and 1997 worldwide. Being an upgrade from its predecessor, Super Mario Kart, it features a similar base to that game in which players select Mario cast members to drive in karts, employing a weapon-based system to benefit the player and hinder opponents, though it has expanded gameplay, such as the introduction of Mini-Turbo boosts from drifting and four-player support. It is the first Mario game to let more than two people play simultaneously. It is also the first game in the series to use three-dimensional graphics for its environment design, such as the addition of elevation, advanced collision physics, expanded camera controls, real walls that can obscure views, and increased aesthetic fidelity; however, the characters, the items, and some track obstacles in-game remain as two-dimensional, pre-rendered sprites, which are rendered for game optimization. Additionally, the game contains unique track designs rather than multiple variants of the same track, and it introduces various track tropes that would later be reused in later Mario Kart installments, such as Luigi Circuit being the first track. Other elements would become series mainstays, such as its racer weight classification, the introduction of Wario and Donkey Kong as playable characters, and several new items such as the Spiny Shell and triple variants of Green Shells and Red Shells.