Who me? Can't stand the game...

I've never heard the real story, but my hypothesis to the CK code is it was probably copied sometime during the development of DK. ITC actually programmed DK, not Nintendo (they designed it). Some of the bugs in CK show up in the early Japanese DK romset (set 3), including the jump cheat, the ladder cheat, and the "How High Can You Try" on the intro screen. It's also got the same level order as the Japanese ROMs. On the non-Falcon sets (the ones that don't say "Crazy Kong Part II"), even the 1981 is in the same spot as it is on DK (it's just missing the "Nintendo" lettering). I'm also guessing that this was done without the Nintendo sound hardware being available to them, since CK uses Crazy Climber sound hardware (and even 2 of the ROM's with the samples from the Japanese set...that's where the "Hiya" sound comes from when he jumps and the "gong" chest beat sound). As to why it's popular, if you lived in Europe, chances are you played CK instead of DK. I think I saw CK here locally before seeing DK, and I always preferred it. It's also different than alot of bootlegs, which were usually just graphical hacks of the originals. This one has so much different on it. I also have a Pac-Man on Galaxian hardware board, which is so bizarre it's awesome

Here's my CK collection. Only thing missing is a marquee from one of the dedicated cabinets (the control panel is there, along with a similar marquee sized for a Pac style cab), and a manual. There's several versions of PCB's there, 3 or 4 CK Part 2 (Falcon), a regular CK (with weird colors) that requires an external sound amp, a Donkey King, a CK on Galaxian hardware (untested, not 100% sure it's CK), and a CK made by Orca, all sitting on my CK Part 2 cocktail. All the boards plug into the cocktail except the Orca and Galaxian boards.