>They don't support Linux with GOG Galaxy

This is a bit of an issue.

For example, Dead Cells offers daily challenges and has a few items locked behind completing them. They facilitate these by using the platform's tooling, which means the GOG version uses Galaxy and Linux users can't access it. And as far as I can tell, there's nothing on the site telling you this, troubleshooting the problem took a fair amount of digging.

A small thing, and I still opt for GOG over anything else, but it can be annoying.