Are you using Galaxy? I think you have to use Galaxy and not just standalone installers.

Edit: that's assuming the games even have their achievements enabled, if the game card doesn't mention achievements then maybe the GOG versions simply don't have them.

Hi shootidodge,
I'm pretty sure that the Darksiders series do not currently have achievements, even if you are using GOG Galaxy.
If you have indeed been playing it with Galaxy and you haven't received any achievements, then I guess that's just confirmation.

Most GOG games released prior to, or just around the time that Galaxy was released do not have achievements. (excluding some, such as the Witcher series, which is to be expected as CDPR own GOG)

The open Galaxy Beta was released ~ 5th of May and the Darksiders series was released on the 11th, so considering that the GOG version was being built prior to Galaxy's release, highly doubt there are any achievements at the present.
Regards! :)

EDIT: I believe that all games that have achievements are shown HERE. Alas, no Darksiders.

Here you go.
https://www.gog.com/mix/games_with_galaxy_achievements
This list has gog games with achievements.
Darksiders are on on list so Galaxy achievement is not available.
May be we will see it in future version of Galaxy.

Thank you guys , you are indeed amazing.
just wanted to know now its confirmed.

cheers

No they don't and that is a real pity, because this translates to TWO UNIQUE, exclusive items you get for free in 2, being UNOBTAINABLE, on gog. One is for PLAYING 1 and the other for BEATING 1. Pauldron of the Horseman and Chaos Fang Scythes.

I played through both, offline, with no "achievements" and it was fine, very enjoyable. Just like i Have played games for decades. Oh and I completed them, do I get a gold star :o)

Using galaxy and finished 2 plays on each and did not get a single one

They ARE enjoyable. And i liked the offline part, too. I didn't even play them on Galaxy, due to the overheating it gets when run from client, like on Steam (posted before on that, as certain steam members on their own forums). I never use achievements and neither do i like them, but this time round, not having them around, leads to those items being missed. I really wanted them...