I still think they have used the unofficial patch that allowed this to be played on newer OS's and higher resolutions.
Which is sneaky of them, wonder if they give royalties to the guy who did it? Probably not :P
They have. System Shock 2 on GOG is using NewDark/2.4.
Hmmm interesting I might pick this up if its not to pricey
only 9.99.....