- Run STConfig
- Set the Main Game Directory to your Submarine Titans Directory
- Rename the following subdirectories to their UPPERCASE names ( ie. video -> VIDEO ) : video, sound, music, data

Running the game should work now without this error.

If the game videos only show black with sound, try this fix :
https://www.pcgamingwiki.com/wiki/Submarine_Titans#Broken_video_playback.2C_showing_as_black_screen

Tried that. Took me a moment, but I finally figured out how it should be done.

I did work, easily, though in the beginning, no sound of music was playing. Thankfully, it was because all the configure settings were turned off. After that, I booted it back up, and everything thus far, the menu, controls and in-game gameplay, all run smoothly and without issue.

Thank you so much. This help was perfect.

Glad it helped :)

Not even sure why it is necessary, seems like something GoG should be able to fix in another update.

It's an older game from like two decades ago. I wouldn't be surprised if they had no idea this game existed, both for its age and for its practically non-existent fandom.

I'd say the main issue likely came for Windows 11 users, which I don't think is even one whole year old overall. Still, this is such a simple work-around I do feel disappointed GOG let this slide. Definitely needs an update to fix this.

Thank you!

also thank you!