Oh I see, I'll look into this. I'm only interested in English personally, but I'll try to see if I need to specify languages individually, for posterity. I'll have to hunt down all the variants I guess

EDIT: Looking at the code I believe you're right. There's a list of valid langs that I can specify so I'll try that. Hopefully it's actually all of them

If you want to be sure to get only English Windows versions, you can make sure by using:

python gogrepo.py update -lang en -os windows
python gogrepo.py download e:\goginstallers\

(where "e:\goginstallers\" is the drive and path where you want to download them)

Remember though that some games have extra language and OS versions also in the extras files. They are put there if they are some unofficial unsupported OS and language versions. So they will be downloaded anyway regardless of what you have as -lang and -os.

Okay, so all OSes (windows, linux, mac) and langs (en, bl, ru, gk, sb, ar, br, jp, ko, fr, cn, cz, hu, pt, tr, sk, nl, ro, es, pl, it, de, da, sv, fi, no) for my ~450 games come down to 3315GB or around 3.3TB

By the way I found this as well, for people that don't feel like reading the docs (I haven't tried it though):
https://github.com/Twombs/GOGRepo-GUI/releases/tag/v1.2_SG

EDIT: tried this with the dev branch of Kalanyr/gogrepoc as well, and the results are the same (3315GB with the same options as above).
However, the parsing process went a lot quicker (55 minutes versus 3 or 4hrs), not sure if it's because it uses Python 3 or another reason. For that reason I'd recommend the Kalanyr dev branch over the original gogrepo