Crazy Kong

Crazy Kong is a Nintendo-licensed adaptation of Donkey Kong created in September 1981 by Falcon for Japan. The gameplay remains relatively unchanged; however, the sprites suffered enough changes to be differentiated from the original. Nintendo had only authorized for the game to be distributed inside Japan, but Falcon breached this agreement by exporting the game into the US, which prompted Nintendo to terminate the license agreement on January 29, 1982.

Differences

 * The words "Crazy Kong" are written out of girders on the title screen, similar to Donkey Kong. Below that is the year "1981", with nothing else.
 * The color palette is different from Donkey Kong. The girders in 25m are green, the ape is orange, and Mario's outfit resembles the one from Super Mario Bros..
 * Some of the sprite graphics in the game have been redrawn from Donkey Kong. For example, most of the sprites for the gorilla are the same. However, the sprites used for when he is pounding his chest are taller than the original and more fierce.
 * Some animation frames have been removed. For example, in 25m, barrels appear to spawn right out of Crazy Kong, instead of him picking up and rolling them like in Donkey Kong.
 * Most of the sound effects in the game are different from Donkey Kong's, due to running on hardware based on that of Crazy Climber.
 * Some consider the game to have a higher difficulty than Donkey Kong as the collision detection in the game isn't as robust as Donkey Kong's, in addition to parts of the game moving at a faster pace.
 * It is possible to complete 25m by jumping off the second girder from the bottom while Mario's foot is hanging over the ledge. When he jumps off, he should fall through the floor and complete the level. This is a glitch that was carried over from the first version of Donkey Kong.
 * The Fireballs on 100m are identical to the fireballs from 25m, 50m, and 75m.
 * It is safe to touch the gorilla in 100m.
 * The heart in between Mario and Lady that appears after completing 100m is now near the round indicator.

Crazy Kong Part II
Falcon addressed several of the problems by releasing Crazy Kong Part II in the same year. Here are the differences from above:
 * Under the title, Falcon's name is located next to the year 1981.
 * During attract mode, a scene shows Crazy Kong breaking out of his cage. This takes place under Falcon's logo.
 * Mario and the gorilla's colors are now fixed but Crazy Kong's animations are still limited.
 * The girders of 25m are now orange and have been shortened so as to not extend past ladders.
 * When Crazy Kong is defeated in 100m, the text "GIVE UP!!" appears in the space between him and Mario and Lady.
 * During round 2 and on (when L=02), two gaps appear in the girders of 25m. The conveyors of 50m move faster.

Elcon Industries
On June 30, 1982, Nintendo of America filled a complaint toward Elcon Industries Inc., an arcade hardware manufacturer based in Michigan that sold Crazy Kong boards. The complaint alleged that the licensing agreement with Falcon explicitly forbade the manufacturing or export of Crazy Kong outside Japan. The case was taken to the United States District Court for the Eastern District of Michigan, which quickly ruled in favor of Nintendo.

Trivia

 * This is the first Mario game in which a character speaks. Mario yells "hi-yah!" whenever he jumps. Ironically, this is a higher pitch version of a gorilla's grunt from Crazy Climber. Lady has unused speech in Donkey Kong, but this was replaced with sound effects before release.