Adventure Mode was first introduced in the second installment of the Super Smash Bros. series, because the original revolved solely around multiplayer capabilities, as the single player portion of the game was considering lacking. As a consequence, Adventure Mode was created.
In Super Smash Bros. Melee, Adventure Mode consists of numerous levels designed as specific characters' universes. For example, the first level is modeled after the Mario Bros.' universe, as it has Peach's Castle in the background and seemingly endless amounts of Goombas. At the end of certain levels, you are pitted against the character(s) from said universe.
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