To help narrow it down I’d try streaming a low-end game that runs very well locally and doesn’t tax the system. If this doesn’t stream well either that would suggest that it’s something specific to the streaming setup, perhaps a networking issue.

It depends. If it’s under your control with your own keys then it can be beneficial. If it’s under someone else’s control (as it is for most people) then it’s a step towards the walled garden.

I am only guessing and extrapolating based on how this usually goes:

• It’s probably possible to get it to run but would take a lot of work
• It’s probably much easier to just run the windows version under Wine

While the Linux kernel usually maintains long term backward compatibility very well unfortunately the userspace (libraries) is a different story.

Looking at the game’s faq the main dependency seems to be SDL. There is no OpenGL or other 3D library requirement. It might also depend on which version was shipped on the CD according to the faq there was an earlier statically linked version (which I am guessing might be easier to get to run) and a later dynamically linked one.

Sales numbers ($) by platform would be interesting to see too.

Correct, that’s what I meant to imply in the first part of my comment. When I research new games I do that from a web browser and that’s when I care about Proton status the most so this works great for that. It does not help when using the Steam client.

I tend to do my Steam shopping in the browser and I use the ProtonDB-Peek userscript. This gives a ProtonDB status badge in the right column under the review links.

This hasn’t been true for years, see the relevent Arch wiki page for example.