Yes, it does work. The new Steam Play was announced quite some time ago, so now you don’t need to participate in any beta. Here’s how it works.

If you have an NVIDIA card, install the graphics-drivers PPA to get the latest and greatest NVIDIA drivers:

sudo add-apt-repository ppa:graphics-drivers/ppa sudo apt update

Now find the latest release:

apt search nvidia | grep "^nvidia-driver"

This will output something like this:

nvidia-driver-390/bionic-updates,bionic-security,bionic 390.116-0ubuntu0.18.04.1 amd64

nvidia-driver-396/bionic 396.54-0ubuntu0~gpu18.04.1 amd64

nvidia-driver-410/bionic 410.104-0ubuntu0~18.04.1 amd64

nvidia-driver-415/bionic 415.27-0ubuntu0~gpu18.04.2 amd64

nvidia-driver-418/bionic 418.56-0ubuntu0~gpu18.04.1 amd64

nvidia-driver-430/bionic,now 430.09-0ubuntu0~gpu18.04.1 amd64

At the time of writing, 430 is the latest. Install it:

sudo apt install nvidia-driver-430

At this point it’s a good idea to reboot, to make sure the new drivers are loaded.

Now obtain Steam:

sudo apt install steam

Start Steam:

steam

Enable Proton for all titles, which is required to make Killing Floor 2 run on Linux, as it doesn’t have an official, native port. Go to Steam / Settings / Steam Play, and check Enable Steam Play for all other titles:

Then you can finally install Killing Floor 2 from your Library, which, in turn, will install Steamworks and Proton, too:

Once KF2 finished installing, you can launch it. Since it’s running on Linux, it will install quite some Windows packages, so be patient.

Aaand that’s it! Just for the sake of proving it, here is KF2 in windowed mode, running on Linux 🙂

Hint: if display is jerky for you, you probably want to enable Vertical Sync.