game not working on steam deck

[Opprobrius]

for some reason whenever i open up mgs5 on steam deck it automatically closes if any of you have a fix it would be much appreciated.

[Death Approaches]

instead of taking the default that steam picks, go into properties and set the runtime to proton 8.x or experimental; I've had issues where it does just that, acts like it's starting, chugs for a few seconds, then gives up and the play button goes back to green, like nothing happened. (regular linux not deck, but it's similar enough it could be the issue)

Do you ever see the main menu? do you play on the PC too? Maybe double-check that it's lowering the settings to deck-compatible graphics... course if it doesn't run, you options are limited, you can manually edit the config. (check pcgamingwiki for the path details where the configs are.)