

Currently, playing the demo/alpha test for Vindictus Defying Fate and it works perfectly out of the box. No tinkering needed. Played it for a solid 5 hours and didn't notice any performance other than frame drops here and there. The game is not optimised but, that's to be expected considering it's only a alpha/demo so, the performance will be fixed on launch. Whenever it launches that is. Game runs buttery smooth on the lower end settings due to bad optimisation had DLSS enabled to help a little bit and it run just fine. The game is difficult but, it's satisfying. It is souls-like after all.

Some NPC dialogue didn't had sound, but it's probably because of the Demo more than a Linux problem
Needed to lower FSR from quality to balanced
I swiched to Experimental and it ran with no issues that I could sense(no laggs or anything similar).
The UI elements are a bit difficult to read on the Steam Deck. Two times bigger would be betrer.
Same as on PC, needed to set Proton Experimental, UI elements are a tad small. Two times bigger would be easier to read.
Needed to set compatibility to Experimental. After that, everything worked.