A LostMediaWiki Discord user DaKoolDood released a ROM of the cancelled GBC game based on South Park which was later reworked as Maya the Bee & Her Friends in Europe and Mary-Kate and Ashley: Get a Clue in United States, after months of contact with the head developer. https://mega.nz/#!A1ozAZYa!KyqmMuo0OTdC4AOXHq15f1mQyKtS3YFWLOoMceNVejg
My mistake, so yeah i'm watching the gameplay and... now i can definitely see why Acclaim decided not to release this.
I played it a bit on my phone, it's not the worst game. If you let the demo roll, it shows you the controls - each of the boys has a special ability and you swap between them with Select. The puzzles are simple enough for now, the three-character mechanic is interesting, and it runs better than what it got turned into (Mary-Kate and Ashley runs horribly somehow). I'd imagine Acclaim didn't release it as-is because it's a fairly foul-mouthed game for a children's handheld. Two ROM hacks later, and they did get two games out of it though. I know a lot of the Crazy Castle games got reworked for European and U.S. release, but I wonder how many other games are just simple reworks of other games - released or not.