"Until recently GOG didn't have an update facility in place for us to offer such a service. Now that they do we will be giving GOG's customers the HD update."
just to be clear, the "offer" that they said was only for steam was the free-ness of the update, not the update, and now they've said the update will be coming to GOG
does GOG charge for updates?
just because something happens that is only available one way doesn't mean it won't be available another way later, and doesn't mean that the thing you don't use sucks because you don't like it
nevermind, i'll go be illiterate somewhere else
You know, the original announcement was released back in early January and they made it clear it's only available for Steam user. Didn't bother to respond to email, tweets about the availability of the patch for non-Steam customer. Did nothing to shed light on the situation even though you can see they regularly update the progress of the HD patch on their twitter and Steam page.
Only after a Steam member directly asked one of their developer on their Steam page, they came with that statement. But that was like 5 or 6 months later from the original announcement, it's not even an official stance and ever since that day we haven't received any news about the patch for non-Steam customer.
Back to the Stranger Wrath HD patch, i don't think they will come out for non-Steam platform soon. Not until they iron out most of the bugs and performance issue. Only Steam offer automatic updating, so it make sense they're working on Steam first.
p/s: The latest Psychonauts update, which included many major improvements is only available on Steam. Although it was different developer, but both share quite few similarities. I don't think it's far fetch to think Stranger Wrath HD PC is Steam exclusive for the moment. Not until i read an official statement.