Darucas: In June last year, the devs on Steam said they released a small fix to allow UI scaling on the Steam version ( http://steamcommunity.com/app/1930/discussions/0/357287304415595014/?ctp=2#c350533172703555738 ), and it was great. But my GOG version still had the small (on 1080/1440p) UI. As with both versions installed, GOG's also had scaling, there was probably a shared file/entry somewhere.

Apparently GOG's version is patched too, it's just that the values for the fix may still be vanilla. So, to make the UI bigger on GOG's, open the registry (Win+R and type 'regedit'), and search for this (the game needs to be launched at least once) :

[HKEY_CURRENT_USER\SOFTWARE\Reality Pump\TwoWorlds\Interface] , you should see 'MaxInterfaceWidth' .

Make a backup of your registry before changing the value if you're unsure of what you're doing (select Comptuer at the top of the list, then File=>Export for a full backup, or simply right-click on 'Interface' for example and Export for a game entries backup. You can even add these entries as Bookmarks!).

Double-click on MaxInterfaceWidth, you can enter a new value (in hexadecimal). Vanilla is 400 (1024), Steam's is 1000 (4096). Then just click OK - you can still check the changes in-game without closing the registry.
I assume you can set it to whatever you want (even smaller than 400), at some point though it just won't make a difference on something smaller than a 4K monitor. I'm using 600 (1536), it doesn't take all the height on my 1440p monitor, and is still very comfortable.

Lord Bafford: There's no such value in regedit, tried to add it manually but it doesn't help with scaling at all.

Any way to increase the UI at resolution 1920x1200 nowadays?

Rick_Aka: Had to change to windowed mode (then increase resolution) and then switch back, to up the display resolution. Worked for me.

Darucas: In June last year, the devs on Steam said they released a small fix to allow UI scaling on the Steam version ( http://steamcommunity.com/app/1930/discussions/0/357287304415595014/?ctp=2#c350533172703555738 ), and it was great. But my GOG version still had the small (on 1080/1440p) UI. As with both versions installed, GOG's also had scaling, there was probably a shared file/entry somewhere.

Apparently GOG's version is patched too, it's just that the values for the fix may still be vanilla. So, to make the UI bigger on GOG's, open the registry (Win+R and type 'regedit'), and search for this (the game needs to be launched at least once) :

[HKEY_CURRENT_USER\SOFTWARE\Reality Pump\TwoWorlds\Interface] , you should see 'MaxInterfaceWidth' .

Make a backup of your registry before changing the value if you're unsure of what you're doing (select Comptuer at the top of the list, then File=>Export for a full backup, or simply right-click on 'Interface' for example and Export for a game entries backup. You can even add these entries as Bookmarks!).

Double-click on MaxInterfaceWidth, you can enter a new value (in hexadecimal). Vanilla is 400 (1024), Steam's is 1000 (4096). Then just click OK - you can still check the changes in-game without closing the registry.
I assume you can set it to whatever you want (even smaller than 400), at some point though it just won't make a difference on something smaller than a 4K monitor. I'm using 600 (1536), it doesn't take all the height on my 1440p monitor, and is still very comfortable.