@Akira,
Are you also going to feature games on your site which were published but look very different from the preview screenshots? I know the C64 GTW site features some games which looked very different in the final version (
Timescanner for example).
On the Amiga, I have some preview screenshots of
Lemmings 2 - the tribes, Blues Brothers, ATV, Donk! Disposable Heroes, Entity, Soccer Kid and many more which did not appear in the final game.
About
Frak!:
The screenshots were scanned from a full-page preview in CU Amiga, August 1991. Maybe I will scan in the full-page previews when I find some spare time.