I'm regrouping here all fixes or workarounds I published regarding this game. They currently apply to the GOG-7 version of the game (2.5.0.7), and follow the same model, i.e. opening a file with a hex editor (only Assembly-CSharp.dll concerned as of now), and overwriting values at a given file offset. For directions on how to proceed, look at the first referenced thread.

Now, to the fixes :
Changing the game language and unlocking all rings and amulets

Unlocking the DLCs

Workaround to the invisible quest rumour cards bug (replaces the burning animation with a move offscreen animation) :
Go to file offset 26AA8A
At this very offset, replace the value D7 with DB

To do :
- Remove the burning sound of the quest cards, since they don't burn any more (easy, I'm just too lazy right now)
- Create a patch regrouping all these changes, plus initialising the RNG with system entropy instead of tick count.

Marvellous!

Again thank you very much, I used Unlocking the DLC and the amulets. Works fine.
For the invisible quest, I already used the solution from LoG forum ;-)