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SLP2000: And as for Carmageddon - I think the main problem here is that only GOG will test it and make it run on modern machines. They (devs) can't allow anyone to sell not working version, as it could hurt their sales with C:Reincarnation.
Miaghstir: On the other hand, other distributors (at least Gamersgate) have used GOG's repackaged installers at the permission of the publisher.