Day One: Garry's Incident (242800) works, but still isn't any good ;)

Compatibility Report

• Name of the game with compatibility issues: Day One: Garry's Incident
• Steam AppID of the game: 242800

System Information

• GPU: Radeon RX 560 Series (POLARIS11, 4GB)
• Driver/LLVM version: Mesa 19.0.0-dev, DRM 3.30.0, LLVM 8.0.0
• Kernel version: 5.1.0-rc1, Ubuntu 18.04 LTS (also tried kernel 4.15)
• Proton version: proton-3.16-8

I confirm:

• that I haven't found an existing compatibility report for this game.
• that I have checked whether there are updates for my system available.

steam-242800.log

Symptoms

The game launches and displays all 2D elements of the game as well as music and sounds.
It responds to the controlls and one has the impression that the game actually runs.
However no 3d elements are displayed (menu backgrounds and game itself), just black.
Game uses UDK (free edition I think ca. 2012) and directX 9.

Reproduction

Download game (I think it cannot be purchased any more)
protontricks 242800 vcrun2008 dotnet40
run game

(I also tried vcrun2010 vcrun2012 d3dcompiler_43 physx)

Start by reviewing steam-242800.log and reproducing the issue with Proton 3.16-8 using the listed protontricks dependencies. Compare the 2D and audio behavior with the missing 3D rendering, then verify completion when the game's menu backgrounds and in-game 3D elements display correctly.