I spent some long hours playing and enjoying Disciples: Liberation (bought it before it became available on GOG). This is not really an open-world but the story is interesting and the character are different from what you can see in other RPG, the setting is not really dystopian but very dark and the more you dig in the inners for the world, gods and factions (you can delve into this if you wish), the more you realize this is not a nice flying unicorns world. The optional investigation into gods and world's real politik is enjoyable even if dark. You can build and respec freely, which allow for real cool experiments and adapt to all situations. About the mature aspect and the PEGI rating : This is definitively 18+. There is blood, torture, sex (wild sex), death, wasting the lives of others, ... and you can get into such decisions or witness the consequences. So it's not even for every adults but if you like to see a tough, dark and unforgiving fantasy RPG world then go for Disciples: Liberation ! One last word about the difficulty : I recommend to play at least in Hard difficulty to get a real challenge. Normal is intended for casual gamers and may prove way too easy for those used to RPG.
