Hi,
I've found the issue. GOG applies 3rd party files to the game setup such as the "goggame.sdb" which is a Microsoft compatibility fix "IgnoreAltTab" which broke mouse function. You have to remove that fix manually from the Windows\apppatch\CustomSDB folder and also from the registry. Then mouse will work normally again.
I have no idea for what this compatibility fix originally should be good for.
The other issue that no game mode selection appears is a bug in the Amnesia.exe caused by the latest 1.41a patch from Frictional Games. They need to fix this!
In addition it could be always useful to update SDL.dll from 1.2.14.0 to 1.2.15.0 with proper mouse fix, SDL_ttf.dll from 2.0.8.0 to 2.0.11.0, SDL2.dll from 2.0.4.0 to 2.0.12.0, add libfreetype-6.dll 2.10.2.0 and update zlib1.dll from 1.2.1.0 to 1.2.11.0. This could help for better stability on modern systems, because these dlls includes the latest bug-fixes and improvements. Frictional Games should think about it. You can download the full updated SDL library in the attachment.
And playing in 4K resolution makes the HUD and font very small. It should be possible to fix the HUD scaling in a next update aswell.
And don't forget to update DRM-free builds from Humble Store and shelf.frictionalgames.com
Humble Store is still on 1.4.0
FG Store is still on 1.3.1
Thank you.
Amnesia_sdl_update.zip (Size: 955.33 KB / Downloads: 274)