There were a few somewhat popular unlicensed clones out there back in the day, as well as a lot of crappy ones on the home computers. Mainly, the game "Donkey K

There were a few somewhat popular unlicensed clones out there back in the day, as well as a lot of crappy ones on the home computers. Mainly, the game "Donkey King" on TRS-80 CoCo (released by Tom Mix Software), later re-released as "The King" with unchanged gameplay. Not sure if the name was changed due to Nintendo or not. The CoCo was filled with unlicensed game clones.