Whenever a game gets released on gog all i see is the description of the original game. I don't ever see a section called gog changes or anything.

The only way that you can find out what changes gog made to a game is by googling it and hoping to find some quotes made in a tweet or something about its release

I had to google it to discover what revisions were made to the newly released call of cthulu. It was something like "fixed vsync and fixed invisible enemy bug" but i just think its lame how this isn't posted anywhere on the store page

Is there a certain secret menu with patch notes or something like that? Im curious about GUN released on gog in 2016

There's a thread here listing patch notes. I can;t find it right off as I've got someone here in frony of me bending my ear for the last 2 hours.

If you go back a page or two on the forums, you should see it.

You can also find it in your library. Click on the game and you should get a pulldown menu with "Change Log" listed. Of course this only helps if you already own the game.

Found it:

https://www.gog.com/forum/general/the_what_did_just_update_thread

Some posts are detailed. Some aren't.

But as TinyE says, any game that updates will show as having a blue dot beside the title. At the upper left of your games library page, there's a selector at the upper left of that page as well.

Hope this helps

Unfortunately Gog doesn't posts changelogs publicly, so it's all up to forum users to keep them updated. ¯\_(ツ)_/¯

There is a centralized location here, and if a game is popular enough someone might have posted the patch history in the relevant subforum (which is not the case of GUN I'm afraid).

In fact, GOG's official blue dots are not reliable.
And many GOG games just have no any changlogs, no matter how many updates they have got. [1]

I start to log them since 8 Nov this year, and plan to list the record at the forum monthly later.
Data I collect so far (since 11 days ago):
Games that have updates: 20
Total updates I got: 25 (Some games have multiple updates. If they appeared in the same day, I only count it as 1.)
Blue dots(official GOG update flags) I got: 6 (That is only 24~30%)

From my still very small logs, 70~76% GOG updates have no blue dot.

[1] I have over 1000 games here. From the log of gogrepo.py, 15% of them have no any changlogs. I am sure some games in the list have had multiple updates.

You could try asking on the GUN game forum or contact Support.

I like how the posters of the first five replies clearly didn't even understand what the OP was asking for. =D Usually, they only mention their built-in fixes and alterations if: 1) they represent a notable departure from previously available versions; or 2) the game was previously so bug-ridden that they want to make people aware that they fixed some of the more major issues. This is, of course, not a hard and fast rule.
Usually, they strive to change only what's necessary to get a game running more-or-less reliably on their various test machines (and if they can't on a given setup, they wont support it for that OS/GPU/whatever).

In the case of Call of Cthulhu: Dark Corners of the Earth, they mentioned some of the most major fixes in the release announcement news post. Besides release announcements, though, take tfishell's advice and check the game- or series-specific forum.

GOG used to list the version on the game pages, but unfortunately they stopped when they revamped the site back in Autumn 2014, and in spite repeated suggestions by users to bring that piece of info back it's still missing.

Currently, there's no official GOG way to check the version and update history of games. Your best resource is to check the thread that was mentioned already ("What did just update"), and from there the respective game fora, or Yepoleb's GOGdb (they're a GOG user).

Aleternatively, you could install Adalia Fundamentanls, a script made and maintained by user adaliabooks, which puts a direct link to the changelog history on game pages. Note though, that GOG doesn't provide a changelog for every update a game receives.

Regarding GUN, the game hasn't been updated since it was released here (Jun 23, 2016), but unfortunately the version numbering used for it doesn't help figuring out the actual (developer's) version. The reason there's no update history for GUN in the game forum is because, according to all sources tracking games, it was never updated since its release here.

And I don't think that popularity has anything to do with posting changelogs in game fora. A handful of us follow the "What did just update" thread, and post changelogs in the respective game fora of any and every game mentioned in said thread, while a few more post changelogs of only games they own.