UnknownUnknown
Game may work out of the box for you, while it may cause some trouble on lower end devices if GE isn't applied.
the framerate appears to be limited to 20ish frame in actuallity if GE isn't used.
The clicks per second that the game allows seems to be limited compared to a native run of the game, making the fishing minigame harder than it should be.
Using Proton-GE is a personal preference. Should work fine using latest steam proton.
Fatal error when launching the game
I managed to install the game, but when I launch it, a "Fatal error" message appears.
"The UE-Toaster_reboot game has crashed and will close: Fatal Error!"
gamemoderun %command%
On versions before 0.12.7 there were problems with the 100% load on the GP, because of which after 1 - 2 frags FPS very much dropped (in my case up to 17FPS).
With the release of version 0.12.7 this problem is not observed.
From my observation, you can reduce the load on the GPU by using GameMode and Proton TKG. Perhaps if you have a more powerful graphics card, the difference will be insignificant.
In game chat sometimes doesn't work
Never starts; splash picture opens, but a "Fatal Error!" message shortly follows.
UE4 Crash on load
Will not even load into the menu. Once you select a game launch mode, you'll be left wondering where the game is for a few minutes before getting a UE4 fatal error
