Tim Duarte and I are working on bringing his game Mean Santa to the Game Boy. I have been programing it and he has been giving me feedback about it. Not that I'd get it completed by Christmas, but perhaps we'll do a Christmas in July and release it then or something.
I have been making it work for Game Boy Color and Super Game Boy, as well as just regular Game Boy, all in one cartridge. These screenshots are from the Game Boy Color mode. The Super Game Boy mode has its own border and color palette.
The premise of the game is Santa has turned grinch-like and wants to steal presents instead of giving them out to the kids. Trying to stop him is the Ghost of Christmas Presents, who wants the kids to get their presents. You control Santa as he's trying to steal the presents in each room. Basically it's sort of like my Game Boy game Ugly Uppity Umpire.
So how this works is if you put the game in a GBC, it will be in color, if you put it into a Super Game Boy it will be in color only a different palette and border, and if you put it in a regular Game Boy it will be black and white. Got it?