In the Donkey Kong arcade game, the first level is named 25m. Its title represents the height that Donkey Kong has carried Pauline up the construction site, continuing the game’s central climbing theme.
The 25m stage is the famous opening screen of Nintendo’s 1981 arcade classic. Mario—called Jumpman in the original game—climbs crooked girders and ladders while avoiding barrels, fireballs, and other hazards. The player reaches the top by judging jumps and routes rather than simply moving through a side-scrolling landscape.
The arcade game’s four main stage layouts are named 25m, 50m, 75m, and 100m. The 50m stage uses conveyor belts and cement tubs, 75m focuses on elevators and bouncing obstacles, and 100m is the rivet stage where Mario removes the supports beneath Donkey Kong. These stages repeat in increasingly difficult combinations. A frequent source of confusion is calling 25m the first “world” or “level”; in arcade terminology, it is the first stage layout, while a complete level or loop can contain multiple stages.