Game works fine "out of the box" but performance, graphics and mouse responsiveness can be further improved by installing Kentie's Launcher and Kentie's Direct3D 10 Renderer. You need to use Protontricks and install the following packages: d3dx10_43, d3dx10, dxvk, vcrun2010, vcrun2015 for the new renderer to work, though.

Wrote a detailed Steam guide: https://steamcommunity.com/sharedfiles/filedetails/?id=2967089130

Definitely playable and enjoyable without any tinkering, if you don't mind a bit of mouse input delay, and low FOV.