Since X Ball was originally a Macintosh game, the early world format utilized Macintosh file features, such as resource forks, that are not available on the Windows side. You will see that there are many worlds created with the first version of X Ball (v1.x) available for download from the user contributed worlds archive, but unfortunately due to their old format these worlds can only be used with the Macintosh version of X Ball. Because Windows users are unable to play these worlds, the price for the Windows version of X Ball has been reduced by $2.00. I believe this to be a fair trade off, but if anybody want's to gripe, I will listen at this address.