System:    Host: blad-pc Kernel: 4.18.4-1-MANJARO x86_64 bits: 64 Desktop: Xfce 4.12.4 
           Distro: Manjaro Linux 
CPU:       Topology: 6-Core model: AMD FX-6100 bits: 64 type: MCP L2 cache: 2048 KiB 
           Speed: 3641 MHz min/max: 1400/3300 MHz Core speeds (MHz): 1: 3239 2: 3595 3: 3626 4: 3600 
           5: 3593 6: 3489 
Graphics:  Device-1: AMD Pitcairn PRO [Radeon HD 7850 / R7 265 / R9 270 1024SP] driver: amdgpu 
           v: kernel 
           Display: x11 server: X.Org 1.20.1 driver: amdgpu unloaded: modesetting 
           resolution: 1360x768~60Hz 
           OpenGL: 
           renderer: AMD Radeon HD 7800 Series (PITCAIRN DRM 3.26.0 4.18.4-1-MANJARO LLVM 6.0.1) 
           v: 4.5 Mesa 18.1.6

Sorry but game won't start - crashed. Maybe it something about PhysX - I've also tried (not) install it - same message.

steam-8980.log

@BLaDZer
This issue possibly isn't Proton's fault, but of the game itself.

Allegedly this problem occurs sometimes when using windows as well, according to users from this Steam forum thread making a copy of cudart.dll and renaming it to physxcudart_20.dll solved the problem.

Can you please try whether this solution works?

Also confirming it works on another NVidia card:

https://gist.github.com/kode54/3ff952f39b407d6f806a6779838f5335

making a copy of cudart.dll and renaming it to physxcudart_20.dll solved the problem.

Can you please try whether this solution works?

yes it's works this way

Game works out of the box for me as well.

https://gist.github.com/sputniktr02/3f410eb3d6206ab7bd35b70c6a1bb12c

Looks like it only works for Nvidia cards out of the box from checking everyones system info in this report.
https://gist.github.com/daasuharo/fbffd8f787ca3062d9ed534376cea3eb
steam-8980.log

RX 580 here. Works out of the box for me too.

It works most of the time but can crash when loading a location. It continues loading but will never actually finish. The error that pops under is: "Pure virtual function being called while application was running (GIsRunning == 1)."

It works most of the time but can crash when loading a location. It continues loading but will never actually finish. The error that pops under is: "Pure virtual function being called while application was running (GIsRunning == 1)."

I have the same issue. I'm not sure if it is a bug with wine or the game itself.

I think it's also an issue on Windows but it happens way more often on Wine.

Still having the issue with Proton 3.16-5. "Pure virtual function being called while application was running (GIsRunning == 1)."

Had that issue today. Yes, I have had it happen on Windows as well, so I know it's not really a Wine or Proton issue.

It seems to happen way more frequently with Proton/Wine though. On Proton/Wine it happened to me every few hours, while on Windows I have seen it once in 20 hours of playtime.

Ah, yeah, it does happen more often on Proton/Wine. I had it happen on some map transitions, but other times, I could play for hours without it happening. Strange.

Random crashes only. It seems problem with cudart.dll physxcudart_20.dll
This is bug from Windows version. Can't fix

I use proton 3.16-6 beta. Nvidia 415.25 proprietary.
Ubuntu 18.10, Linux 4.18.0-13-generic #14-Ubuntu SMP Wed Dec 5 09:04:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

My PC info from Steam->System Info https://gist.github.com/Sebastian1978/39ee20ace2e5ada5d0b8614914e7334b

EDIT: Multiplayer works.

Currently having crashes either when I try to fast travel or load a new map and sometimes randomly throughout gameplay.
Running an rx 6800, and using 6.20-GE-1 but have also had the same issue with other proton versions
steam-8980.log
00

Compatibility Report

Name of the game with compatibility issues: Borderlands (8980)

Steam AppID of the game: (8980)

System Information
Distro: kDE-NEON

PPA: Kisak_PPA(s), Canonical-X-Staging_PPA, Canonical-Proposed_PPA, UDC_PPA, Graphics PPA
Repos: Ubuntu Proposed and Backports enabled.
Repos: kDE-NEON_User_LTS_ stable.

GPU: nVidia GTX 1050 (2G_vRAM)
Driver/LLVM version: nVidia 495 from Launchpad Graphics PPA

Kernel version: 5.13.0-23 - generic w/ extra nvidia sig,object and modules packages

Proton version: 6.3-8c w/ Steam Client Beta w/ Runtime linux/sniper/soldier - [client-beta ]

Link to full system information report as Gist:
Gist. Sys. Report
https://gist.github.com/username-murphy/cecc0bf365612034a71fc2ccc8aa1484

Borderlands should be considered for whitelisting if its not already.
Only issues I found was:

1. what I think is a game bug at " The Doctor is In" / Dr Zed Open Building 3" Panels either side of the door of the dome building before opening Dr Zeds door look like a test pattern with letters in them. Once that level is completed the Panels look normal.
2. Although using a gamepad the game prompted at the begining to use Keyboard keys to navigate and movement like the game didnt recognise the gamepad but it did.

Other than that the game is working as expected.
As a paying customer Im more than happy with the performance using Proton.
Im struggling to upload this log at the moment. Ill attach it later when I work out whats going on.