That sounds very good! I’m curious and looking forward to it. Of course such games also make fun against human friends and I also play "Puzzle Bobble" on the C64 against some mates from time to time, but it's a big improvement, when you don’t need anyone else for it and you could play in the versus mode at any time, because CPU opponents are always there. *lol* Therefore I play "Bust a Move 2" (Puzzle Bobble 2) quite often on my PSX and on my N64.
And if CPU-opponents are included, on such a game on the C64, it would be important, that they actually play well, for instance, by offering adjustable difficulty levels (as it's the case in the "Bust-a-Move 2", "Bust a Move 3" and "Bust a Move 4" games, for example with "easy", "normal" and "hard" modes), so that the game remains engaging, even for skilled players, by using the "hard" mode.
That would be great! Good puzzle games with strong CPU-opponents are always fun, even in the long run.