Onslaught's release is made from the tape files. I know as I was the one sending the disk version found by my group mate Black Beard to GTW64 after Onslaught's release. Onslaught gets all originals sent in to GTW64 by the way, and it has been like that for years, so I am not surprised. One interesting thing is that the disk version actually had protection, which the tape version did not have. We supplied a version with the protection removed as well.