Isn't that for sure?
It's very sure since the latest update added German text to the game :)
I mean this because you wrote "Subterrain SOLL deutsche Texte haben".
This means that you are not sure that this is so. When you are sure of that, it must be "Subterrain HAT deutsche Texte".
I wrote this "soll deutsche Texte haben" when I don't own this game on GOG and therefore can't check if this is true or not.
I hope, you understand that I mean.