Breakthrough Hit: It was this game that brought Nintendo into the video game industry, after the company spent an entire century producing other things.
Fan Nickname: Level 50m is often called "pie factory" because of the sprites used there. In reality, however, these are tins of cement.
No Export for You: In a bizarre twist, the original arcade versions of Donkey Kong, Donkey Kong Junior, and Donkey Kong 3 (and Mario Bros., as well as Popeye) were written by Ikegami Tsushinki, a manufacturing company which developed the game for Nintendo. Unfortunately, there was no contract between Ikegami and Nintendo for the source, so Nintendo does not own the original arcade game code. This is why Nintendo cannot sell the arcade version of Donkey Kong for its consoles, but is free to sell ports (i.e., the later NES versions) remakes and updated versions instead.
Considering that a near arcade perfect port exists in Donkey Kong 64, this may also be a reason why that game has not seen a rerelease. (It should be noted that DK64 requires you to play - and beat - the original Donkey Kong in order to reach the final boss.)
The Pete Best: Pauline has fallen into near-complete obscurity since the original game's release.
Port Overdosed: Virtually every console and computer of the era had Donkey Kong released for it, and so have many since. Among 1980s arcade games, its omnipresence is surpassed only by Pac-Man.
Serendipity Writes the Plot: Mario had a hat for two reasons. For one, Shigeru Miyamoto claimed that he was terrible at drawing hairstyles, but the major reason was that when Mario fell, the engineers would not be able to show his hair sticking up.
His mustache, large nose, and overalls also came into being because they would be visible and recognizable at that resolution.
Urban Legend of Zelda: Theories about what the name meant. One example, from a review in Acorn User magazine, was that the name was supposed to be Monkey Kong, but someone made a typo. In actuality, Miyamoto thought that "donkey" meant "stubborn", so he intentionally named the character Donkey Kong.