After the latest update on GOG (3.0.146.949_HOTFIX), I can't launch the game with or without Galaxy running. The error tells me that [i]steam_api64.dll[/i] is missing.
Looks like we both registered and posted around the same time for the same issue lol
I just noticed that it looks like they rolled back the latest patch. I still couldn't launch so I used verify game files and it fixed it. Patch rollback until the hotfix works right I guess. Quick turnaround though! :D