Death Road to Canada. The Windows/Mac versions are 5 updates behind (outdated by 1 year), while the Linux version is 6 updates behind (outdated by 2 years).

Hero's hour received an update today. It is version 2.8.2 and it can be removed from the list. On the spreadsheet it says that it's missing version 2.8.3 but when I looked on the other store I only found v2.8.2

EDIT: It seems that they actually uploaded 2.8.3 on GOG as well.

SClash seems to have updated to 1.1.65 :). Still missing the cosmetic DLCs though.

The 2007 version of Sam & Max Save The World is still glitched nowadays compared to the Steam version as it has always been since its release, way before the remaster.
In the first episode, at one point, a character (Sybil) is invislbe and cannot be interacted with unless you click on a random spot of the room, which makes her appear. This is borderline game-breaking as new players may not find the way to "fix" this issue by themselves.
The end credits scene of Episode 6 also has glitched visuals.

The only fix applied by Telltale at the time was rolling back the Episode 5 version. The rest of the issues are not addressed.
This is far from simply being not updated to the latest patch or having a missing DLC... The base game is broken.
Forums post from multiple years seem to show that GOG could not convince Telltale to update the build to fix these issues but since Skunkape Games have taken over the game, maybe they could do something (like simply updating the game to the same build as on Steam)

not sure if its mentioned in this long thread, but the quake remaster has a new episode that released on 6th August and we still don't have it here. Also after three ducking months viscera fest finally gets the latest hot fix.

Iron Nest has achievements on Steam, but were not implemented on GOG

Better asking machine games that question.
Not really second class, alot of games on here don't include achievements because you can't port them over from steam. This thread for games that are outdated or missing key features achievements isn't part of that list.

machine games only made the episode, its bethesda that maintains it

A new update for Fallout 4 has been released this week:
https://fallout.bethesda.net/en-US/news/fallout-4-update-august-18th

Skyrim also got updated this week:
https://elderscrolls.bethesda.net/en-US/news/skyrim-update-august-20

nvm

Terraria updated a couple days ago elsewhere, but not here. However evidently this was an issue on the GOG side and not Re-Logic snubbing us.

Had some bizarre upload issues with GOG yesterday (literally tried it 8-10x), working through that still. Seriously, we tried to update GOG at the same time as Steam... - Loki, Head of Business Strategy at Re-Logic, yesterday on the official Terraria forum.

You're lucky to get a reply I guess, I sent them like 2 emails with several gentle reminders but received none.

Their message at least gives me hope that the game hasn't been abandoned here.

--------------------------------------------

In other news

The Linux version of Mount and Blade - Warband including the DLC is outdated compared to the Windows one.

Windows is on par with Steam 2.072, Linux is 2.069 though.

Will try to email developer about it.

Can you try also emailing the devs behind the quake rerelease on when the new episode is coming to GOG?

Donut County is missing the update from October 2025, the latest update on the GOG version is from November 2018.

The Darkest Files
• Missing upcoming game DLC: The Darkest Files - Battalion
• Missing extras DLC: The Darkest Files: Prosecutor Edition Upgrade
• Missing extras DLC: The Darkest Files: Supporter Edition Upgrade
• Missing extras DLC: The Darkest Files: Soundtrack
• Missing bundle: The Darkest Files - Complete Edition

I'll need to go nag these guys...

Also, if anyone wants a smug laugh, I have found a game with a soundtrack on GOG, but not on Steam xD:
The Phantom Fellows
• GOG-present extras DLC that's missing on Steam: The Phantom Fellows - Soundtrack
I'm adding this to the cart immediately LOL.