1993 original floppy release
1994 CD-ROM - full speech and additional narrative history of the lands by Patrick Stewart
1996 CD-ROM - "special" white label European release. No idea what's so special about it, even though I have this. Doesn't appear any different from the '94 release, except maybe the box art.
Virgin re-released some of its games under the "White Label" line, which is nothing more than a "nice price" line. There is no special content in it. I also own the White Label version, although I would throw it away as soon as I would get my hands on the original release version.