Seems like this might be part of the issue:
770.575:0027:0028:warn:module:load_builtin_dll cannot open .so lib for builtin L"Steam2.dll": /home/gabriel/.steam/steam/steamapps/common/Proton 4.2/dist/lib/wine/steam2.dll.so: cannot open shared object file: No such file or directory
770.583:0027:0028:warn:module:load_dll Failed to load module L"Steam2.dll"; status=c0000135
Tried with the new 4.2.4 but same error

Based on a protondb report for metal slug which has a similar issue, I took libGLESv2.dll, libEGL.dll, and d3dcompiler_46.dll from another game (Shantae: Risky's Revenge, the same as in the aforementioned report) and copied them them into the game's folder, overwriting the existing files.
With these new files the game runs on proton 4.11-7 and from my brief testing the input latency seemed okay, but I noticed a fair bit of audio latency. I'd seen some mention of audio latency in the steam reviews and on the forums, but I don't have the issue myself when playing on Windows 10.
This game was just updated, replacing the old DotEmu version with one developed by Code Mystics. In addition to providing better emulation and rollback netcode, I'm pleased to report that it launches out of the box with Proton 4.11-12. I haven't tested each mode in the game - just spent 15 mins or so playing around in training mode - but it appears to run without issue.
I can confirm that is now running out of the box (tested again with Proton 4.11.12)
The online match also works
New log
@kisak-valve I request this topic to be change to an whitelist request.
Thank you.
Hello @FurtadoPires, please grab the whitelist request template, copy it over to the comment box on this issue report, and fill it out to when requesting that a compatibility report be switched over.
@kisak-valve done
Thanks, is anyone else seeing an issue that would block this game and Proton 4.11 from being whitelisted?
proton 4.11x2 2020-02proton 4.11-12x1 2020-01proton 4.11-7x1 2019-10proton 4.2x1 2019-05d3dcompiler_46.dllx1 2019-10libegl.dllx1 2019-10libglesv2.dllx1 2019-10steam2.dllx1 2019-05
Whitelist Request
System Information
I confirm:
Playbutton in the Steam client is sufficient.Issues
No problems with either single player / Multiplayer
Proton Log