This article lists some of the games in my Steam library, categorised by whether they do or don't run on Proton and Vulkan on GNU+Linux. It seems my eschewing of Windows as a gaming platform/OS was a little premature.

Games that Do Function/Run

• BEEP
• Deus Ex GotY Edition
• Don't Starve
• Fallout Shelter
• Half Life: I haven't tried the add-on packs such as Blue Shift
• Heretic — Shadow of the Serpent Riders: Runs through DOSBox
• Painkiller — Black Edition: Runs in a small window, regardless of set screen size/resolution
• Reus
• Rytmik Studio
• Rytmik Ultimate
• The Binding of Isaac
• Wolfenstein 3D and Spear of Destiny: Runs through DOSBox
• World of Goo

Games that Don't Run on Steam (GNU+Linux Version)

The following games either don't run at all or do not function completely on GNU+Linux using Proton and Vulkan:

• Bridge Constructor Portal: Fuzzy white blob with thick black lines where the bridge construction area is meant to be.
• Doom I and II: Temperamental. I've been able to install and run it without issue before, but now it gets stuck on the copyright/logos screen.
• Hitman — Codename 47: It just shows a black screen. Changing configuration from Direct3D to OpenGL makes no difference.
• Sega Mega Drive and Genesis Classics — Sonic the Hedgehog: It just shows a black screen
• Serious Sam Classic — The First Encounter: Hangs/Freezes during introduction scene video
• Serious Sam Classic — The Second Encounter: Hangs/Freezes during game play
• Serious Sam Classics — Revolution: Hangs/Freezes during introductory video

Unfortunately, I can't uninstall them due to some of the Steam client's menu items being non-functional.

Games I've Yet to Test

There are a whole bunch of these (too many to list).

Conclusion

It seems that the older a game is, the less likely it is to run (not including those that run on DOSBox.)

It seems to me that if I want to fully enjoy playing all the games in my Steam library, I'm going to have to run a Windows rig for the sake of compatibility, which is disappointing. I was really hoping that the combination of GNU+Linux, Proton and Vulkan would be up to the task of making all my games playable on a GNU+Linux rig.

To add insult to injury, the Windows 7 installation ISOs I downloaded don't seem to be bootable (at least not when selected from the boot menu).