Might not be much either, but maybe only the games in-which "unknown developer" wrote on the picture accompanied to the download page "this is not a screenshot"- are actually connected.
All in all, "this is not a screenshot" is written only on "On the Edge", "DPTG" & "Six Books" [the word "screenshot" is mentioned in "Tits & Boobies" and "en wye" though]