@Kedawa,
Yes this seems to get covered every few months or so. In a nutshell, some developers would only use the NTSC graphics area to save programming time doing different screen sizes for other countries. This is great but for some reason that I don't understand, the sounds would sometimes get messed up when you played a PAL game on an NTSC system.
I remember not understanding this at all back in the early 90's and was blissfully unaware that I was missing the little pin between the flippers when playing pinball dreams on my NTSC A-500 and 1084 monitor. I also attributed occasional messed up sounds with bad cracks and not the fact that the games were PAL.
Now that I have a PAL TV and a PAL CD32 (and 1200 actually) it makes a huge difference in games that I though were working before but now look and sound much better. Cannon Fodder is another example of a game that would play ok in NTSC but the intro music would be all messed up.
Somewhere, and I think Camy has the link, there is a list of CD32 games and how they play on what systems.