I got the older PacMan one, so maybe it's a software update? I'm just not sure. I was hoping that one of the several people who have already hacked this would give me some hints, but maybe I've got this in the wrong forum... I plan on using a J-Stick anyway, so I can change it from 4 to 8-way, so I'll answer my own questions in time. Thanks for the reply Grasshopper.

Just for future reference, Bosconian will play in 8-way mode. It's just the restrictor in the joystick that causing the 4-way gameplay.