Back to the Future: Ep 4 - Double Visions (94520)

Compatibility Report

• Name of the game with compatibility issues: Back to the Future: Ep 4 - Double Visions
• Steam AppID of the game: 94520

System Information

• GPU: AMD HD7770 2GB
• Driver/LLVM version: Mesa 18.2.3, LLVM 7.0 (Padoka PPA)
• Kernel version: 4.15.0-38-generic
• Link to full system information report as Gist: https://gist.github.com/GlacialTurtle/82e549d61b5b0e2e6e09ff70ec57ede3
• Proton version: 3.7-8

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.

Symptoms

Episode 4 (appid 94520) specifically does not render correctly, but the other episodes do.

Comparison images between episode 3 (appid 94510) and episode 4 (appid 94520):

https://imgur.com/a/MvK1Vej

As the camera moves away from characters, they become darker in appearance which also produces noticeable triangular artefacts. Other surfaces e.g. in the initial main menu background also don't render correctly.

Tested on both AMDGPU and Radeon kernel drivers, both produce the same results.

Reproduction

Simply playing the game.

Start by reproducing Back to the Future: Ep 4 (Steam AppID 94520) with Proton 3.7-8 and compare its rendering with Episode 3 (AppID 94510), focusing on the darkened characters, triangular artefacts, and menu surfaces. Check whether the behavior remains with the reported AMDGPU and Radeon drivers; done means Episode 4 renders correctly without those artefacts.