I added Castlequest to IFDB yesterday and I got this comment:
@FriendOfFred is right and I suspect that the text “This game requires an interpreter program - refer to the game’s documentation for details” is there because the file type of the link is classified as “Story File”. But what should it be? The only file type that is reasonable close is to classify it as “Application” but then I have to specify for wich system and there are no generic system for Windows. You have to specify wich Windows, the alternatives being from Windows NT 3.5 to Windows 8.1 (Windows 10 is missing).