On Wed, 20 Dec 2005, sicklittlemonkey wrote:
Excellent. Undocumented opcodes are one of my hobbies! This adds one to the short list of games that I know uses them. (Others are Bug Attack, Ms Pacman, Roundabout.)
I've removed or at least disabled (with someone's help here) a hack-validity check from Ms. Pac-Man which I believe was where the illops were exclusively used. I can send this if someone wants to check.
The patch also implies the result of the illegal opcode is used. If so, it's the only instance of that I've seen.
I think it's done a lot in C64-land. -uso.