Pls, check price in the Russian region.
It's a huge difference with the Steam price.

GOG-1700р
Steam-500р

Maybe it's a mistake.
Just saying.

It's not a mistake. Some genital wart of a person was abusing the GOG regional pricing to buy up copies of Factorio at RU pricing, and selling the generated retail keys Factorio devs use for upgrading the account at regular US price. Which led to the devs equalizing our region's price with the rest of the world.

Thankfully the Steam version is unaffected. I recommend getting the game there if you're in Russia.

Of course, this wouldn't be much a problem if the price was actually sensible for the game rather than 30 dollars.

In polish region also that game cost much more on GoG than on steam.

This is one of the games, which tries hard to prevent you from buying it.

Same issue in Brazil. 50 Reais on Steam and 171 Reais on GOG

The dev forgot to set a regional price. We can contact the dev or GOG support to solve this issue.

lol no success looks like