If it's possible to change the difficulty names in Rubia's Mod settings > Map
Difficulty 1, for instance, is just "micropenis". That should probably be changed to "Easy", to fit with 2 and 3 which are simply "Normal" and "Hard".
4 and 5 are "Pyanodons" and "Engineer Must Die", respectively. Those aren't offensive, but 4 is mildly 4th wall breaking. (Maybe "Very Hard" instead?)
5, I don't actually have a tremendous problem with since the name is pretty in line with what the difficulty is, it's not too tonally dissimilar from vanilla's "Deathworld", but it would stick out amongst Easy to Very Hard. It could be something like "Extreme" to fit in, but I'll leave it up to you.
