Well, here's a bit of a nuisance. Ghost of Tsushima DIRECTOR'S CUT is launching on May 16th and the developers have explained how it will work on Steam Deck but it's a mixture of good and bad news.
Sadly on Steam Deck and presumably desktop Linux too, since they both use Proton, you'll only be able to play single-player. At least, for now, until Valve can sort out whatever the issues are preventing the online mode from working.
Here's what the developer said:
Steam Deck support
We know many of you are eager to play Ghost of Tsushima Director's Cut on handheld gaming devices like the Steam Deck. We're happy to share that the single player experience, including the Iki Island expansion, can be enjoyed on Steam Deck and similar handheld gaming PCs as we’ve worked extensively to optimize performance and deliver the best possible experience on these devices.
You may notice that Steam marks the game as 'Unsupported' for Steam Deck. This is due to the Legends co-op multiplayer mode requiring Windows to access PlayStation Network integrated features.
For those confused, the game will have a brand new never-seen before PlayStation Overlay shipping in this game first, which hooks into the PlayStation Network for things like Friends, Trophies and more.
It may very well be the case that for now, Proton (the Windows compatibility layer), is just missing some features that need to be hooked up in a future Proton release. We've seen this sort of thing happen in the past and eventually Proton updates catch up with what's needed. So, all hope may not be lost, we just have to wait and see what Valve have to say about it. Concerning to see though, because no doubt a lot of future Sony PlayStation titles coming to PC will have this new PlayStation Network overlay. I've emailed Valve for info on this.
Worth pointing out at this point too, just like with Helldivers 2, the game has been restricted on Steam with various places unable to buy it due to the PSN requirement for the online mode.
Article taken from GamingOnLinux.com.
LinuxGamesTV May 14
MasterSleort May 14
Arehandoro May 14
Quoting: MasterSleortI have been looking forward to this game ever since Sony started releasing games on Steam. As long as the game works in single player without requiring internet, I am happy. I hate the single player games that I cannot play on the go, because I need some sort of internet connection. The fact that they say they have tried to optimize the game for Steam Deck makes me so grateful!
Mainly came to say this :)
. Sony is really getting on my nerves.
benstor214 May 14
Quoting: Liam DaweWorth pointing out at this point too, just like with Helldivers 2, the game has been restricted on Steam with various places unable to buy it due to the PSN requirement for the online mode.I understand it: places like Greenland, Japan, the baltics like Estonia, Latvia, Lithuania, city-states like Gibraltar, San Marino, and especially Monaco are rather underdeveloped third-world countries.
Why?
WHY? It makes absolutely no sense at all.
Quoting: PenglingErm, weren't there people out on the interwebs saying a couple of weeks ago that PSN requirements weren't going to lead to new launchers and similar stuff being added to future Sony PC releases?There are people on the Internet who say anything.
This one's been flagged as having PSN integration for ages, and was always going to be part of having PSN as a Rockstar/EA/Ubisoft-style parallel store and launcher move. The lesson recently was that you can't accidentally sell games that need a thing in countries where you don't have the thing.
Quoting: CatKillerThere are people on the Internet who say anything.Yeah, I know.
This one's been flagged as having PSN integration for ages, and was always going to be part of having PSN as a Rockstar/EA/Ubisoft-style parallel store and launcher move. The lesson recently was that you can't accidentally sell games that need a thing in countries where you don't have the thing.
My point was simply that there were statements made just a matter of days ago, when people raised concerns, that've aged rather like milk. 
I just found it kinda funny!
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