If you experience flickering when running this game in fullscreen or borderless mode, you NEED to run Wayland to fix it. I've tested Fields of Mistria with Mint, Zorin and Fedora running Cinnamon, Gnome and KDE to find out that it's the X11 / xorg graphical subsystem that causes this flickering. If you're on a Debian-based Distro and play this game a lot, it might be worth to switch to Fedora, Arch or an Arch-based Distro for Wayland support and more up-to-date packages.