For those who still cannot start the game with the provided DLL file in the GOG install, I have discovered that the D3d8.dll provided in the AlpyneDreams/D8VK utility has greater compatibility and does work. The Windows 11 computer that failed to run the game does so with this DLL. While I cannot guarantee 100% compatibility with all systems, it DID resolve my problem on the one Windows 11 computer that failed during my review.

Below is the link. The utility is primarily for Linux and only the DLL is required. Copy it and replace the one provided by the GOG install.

AlpyneDreams d8vk Utility

I don't know where or how you found this... but thank you so much! It works on Win 11 now. Awesome

I found it in a rather forgotten post on Steam about the same issue. It was definitely a case of great luck.

I prefer to play it inside a window (it works in Windows 10)

https://www.youtube.com/watch?v=BD-bTqY5b8Y

Note: make you sure you delete d3d8.dll and dangerouswaters.ini after a fresh install before using this, or it won't work

Maybe you could test it in Windows 11

FPSChasly's method doesn't work on all systems. Subsim was my first go-to when I encountered the failure to run issue. The alternate DLL I posted did resolve the issue. The system in question was a Win 11 rig.

I see. Sorry, I'd wish it would work with w11, because if you're like me, you want to have the manual close to the game window while learning it. All the best!