NES Game

Yes, there was a Karate Kid 8-bit Nintendo game. My opinion of the game is that it really sucks. It is your typical side scroller game with a few bonus levels involving catching flies and breaking ice.
Game ratings:
Lane3 out of 5
Mr. Groove2 out of 5

To get the game:You can get the game in one of two ways.

Way 1. You can buy the game at Amazon for as low as $3.29

Way 2.You can download and install the Nesticle NES emulator, Dos4GW which makes the emulator run at normal speed no matter how slow your computer is, and The Karate Kid ROM and unzip it into the Nesticle directory. You need to use Winzip to unzip these files, download it HERE if you don't yet have it. You can then play the game on your PC for free.

NOTE:I cannot help you with this since I know little about emulation, check out an emulation site for more info. The ROM and other linked files are believed to be public domain, if the owners want the link(s) removed from my page please email me.