All games, or most games in pacman.c? Almost all games in that driver use 4-way joysticks, but not all (jumpshot, ponpoko, lizwiz, drivfrcp, & porky are 8-way or 2-way). If these few work, and other 4-way games on different drivers don't, I'd guess it's a mame 4-way input bug. (To get a list of 193 parents, go to MAWS and do the deluxe search: search resource type: parents and control: joy4way.) Could you test?
If that's not it, it's ... something else. Umm, yeah, we'll worry about that if the above guess isn't right.
