Alien Shooter 2 is missing an update that adds Russian language:

https://store.steampowered.com/news/app/33120/view/2912096327579186034

They have a Wartile channel in the Deck13 Discord:
https://discord.gg/deck13

It doesn't seem very active, but maybe you might be able to get some answers.

I contact the developer through facebook and he said he drop the title here on GOG.

Sorry, I don't understand. Do you mean he's going to update it? Or do you mean he's no longer supporting the gog version?

The second one, he abandoned all their games here on GOG.

Well that sucks. Thanks for the info anyways.

Looks like another developer for the blacklist.

More issues from the current sales:
Epistory - Typing Chronicles is missing updates since November 2018. According to SteamDB, the Steam version has received 5 updates since then, one of which comes with a patchlog.
Nanotale - Typing Chronicles is missing the soundtrack DLC.

Wow I knew that GOG lagged behind Steam in terms of updates but I didn't know it was this bad. This is nuts. Even if it was only 1 game on this list, it would be too long. This is the problem with Steam's essential monopoly on the digital PC game market.

And this is just the ones we know about or users have reported. Unfortunately I'm probably going to limit my future purchases on GOG as I'm a very patient gamer and publishers tendency to treat GOG users as less important than Steam is at cross roads with my desire to play complete games years after they release.

It's difficult to trust that new games released DRM-free will get the updates to match Steam unlike older games such as the Arkham series, Tomb Raider or Mad Max. Those I will probably continue to purchase here

Tried to contact them through discord. Unfortunately the person who managed their channel no longer works for Deck13 and thus can't help. He or she advised me to contact them through facebook but since I don't have an account there (yeah I know I'm strange that way) I can't help any further. If anyone is willing to try that I would appreciate it.

I asked about it on the Discord, so we might get a response tomorrow during working hours in Belgium. From what I've seen of the Discord, there are a couple GOG users on there and I've seen some people bring up GOG issues which were then promptly fixed - so hopefully they just forgot about Epistory on GOG ever since they started working on Nanotale (which should be up-to-date as far as I can tell)

I can totally understand you. I've only started using GOG as my "main store" about one-and-a-half years ago and I already have this voice in the back of my head going "just go back to Steam, you never had to deal with this sh*t over there, Steam's gonna be around forever anyways, so who cares about DRM..." But if you're gonna buy from other sources, be aware that other non-Steam stores seem to also have issues keeping their games up-to-date (I posted some examples in this thread a while ago). So yeah, this is a case of "buy on Steam and be sure to always be up-to-date or buy anywhere else and take a risk"

Just in case you're thinking of buying another game on GOG in the future, you can compare game builds with these two websites (in case you don't know them):
https://steamdb.info/
https://www.gogdb.org/

Turnip Boy Commits Store Segregation

Already mentioned in the doc, but there's another issue: the Linux build was re-introduced on Steam and Itchio back in September 1, and so far it wasn't made available on GOG as well.

Since no one asked in the devs' Discord about adding the Linux build here, I asked it just now. Now waiting for a reply (hopefully positive).

Thank you. I'll give it some time before asking gog for a refund, which may not work given I bought the game around June or July. If they refuse a refund, i'm gonna clear my wishlist of any newer games as I won't be buying those on gog anymore after getting shafted with yet another game that hasn't gotten the latest bugfixes.

I've got an update about Turnip Boy Commits Tax Evasion (that was quick). Also got an update about the other issue the game has. Posting the entire conversation so no information is lost. tl;dr in the end.

Me: One of the devs: Me: The dev: Me: The dev: Me: tl;dr: challenges use Steam's leaderboard DRM so they'd have to rework the challenge systems to bring it here; and about Linux they'd rather not support Linux here than not adding GOG's SDK to it (but they might consider adding the Linux build from Itchio as part of GOG's goodies).

Dying Light: Platinum Edition is not on the list.

It doesn't have Linux and Mac builds, not sure about other problems mentioned for Dying Light: The Following - Enhanced Edition (i don't have these games).