50m

50m (or 50 m) is the second level of the Donkey Kong arcade game and Donkey Kong for the Game Boy. This level has a series of Conveyor Belts which run along the second, fourth, and fifth floors with the former two carrying hazardous cement tubs. This level has hammers to smash Fireballs and cement tubs. There are also ladders, which Mario must climb. The top ladders will also disconnect and connect when Donkey Kong beats his chest, which he does instead of throwing barrels like in the first stage. The oil drum in this level is in the middle of the stage, and produces more Fireballs to burn Mario. Lastly, because the top floor is a Conveyor Belt, Donkey Kong moves left to right throughout the level. However, he is harmless in this stage and Mario only has to get up there to beat the level. As Mario reaches the top, Donkey Kong takes Pauline again and climbs up to 75m.

Enemies

 * Cement tubs
 * Fireballs
 * Donkey Kong (boss)

Pauline's lost items
Within this stage, Pauline's lost items can be found in the following order and in the following places: Note: The Hat and the Parasol switch places in the Game Boy Donkey Kong.
 * Bag: Stays on the ground, between the two ladders in the middle.
 * Hat: On the far left of the center platform above the first Conveyor Belt.
 * Parasol: On the girder located at the right of the platform with the hat on it.

Trivia

 * If Mario is on the portion of a ladder that retracts, he will appear to be climbing on nothing. This activates a glitch that allows him to climb all the way down through the wraparound screen and end up at the top which registers Mario as having completed the level. This is similar to the glitches found in 25m but less useful as the place to trigger the glitch is just before the goal.
 * This is the only level where Donkey Kong moves, though technically it is the Conveyor Belts which are moving.
 * This level was omitted from the NES version for unknown reasons (presumably the cartridge's storage limitations), though a newer port of the NES version (named Donkey Kong Original Edition) includes this level pre-installed for the European release of the Mario 25th Anniversary-styled Wii. Unlike the arcade version, Donkey Kong stays noticeably still, as he is considered a background object as opposed to a sprite.