And Half-Life 2 has been updated to add some apparently Deck-specific features including HUD scaling and aspect ratio independence, Vulkan support, fixes for various bugs and a few other nice things like ultrawide support:
There are some interesting results there, I find it odd that they bothered to test several VR games when they knew none would work since Steam OS doesn't support VR! Dark Souls games work (does that mean Elden Ring will too?), maybe I'll finally give them another go but maybe not in public because no one needs to see a 35 year old man smash a toy to pieces because he lost some souls doing something dumb.
@Terronium-12 looks like they're on track for an (end of) February launch.