IL-2 Sturmovik: Cliffs of Dover Blitz Edition (754530)

Compatibility Report

• Name of the game with compatibility issues: IL-2 Sturmovik: Cliffs of Dover Blitz Edition
• Steam AppID of the game: 754530

System Information

• GPU: NVIDIA GeForce RTX 2060 SUPER
• Driver/LLVM version: NVidia 470.57.02
• Kernel version: 5.8.0-63
• Link to full system information report as Gist: Here
• Proton version: 6.3.5

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

The game fails to launch at all.

Looking at the proton log, it complains about DLLs that it can't open. (Log 1). For each of these I created symlinks in the same directory as the main executable, which did seen to resolve these errors. After doing this this, there are null reference exceptions in the log and lines like this (Log 2):

EXCEPTION handling: System.InvalidProgramException: Invalid IL code in <Module>:?A0xe813d47e.??__F?A0xe813d47e@_Fac_tidy_reg@std@@YMXXZ (): IL_0024: calli     0x11000144 

Which are a bit beyond my ken.

Reproduction

Hit play; game listed as running for a few seconds, then exits.

steam-754530_log_1.log
steam-754530_log_2.log

Start by reproducing the launch failure with Proton 6.3.5, then inspect steam-754530_log_1.log and steam-754530_log_2.log, including the missing DLL and InvalidProgramException messages. Done means the game launches successfully from Steam without the reported errors.