I don't know, one mission for the Elves was really tough for me, the one where you have to go through underground passages to reach the lower left garrison... later I found out that there were some bugs and a patch was released, but I completed it without the patch, it was quite a struggle. But playing on the hardest difficulty level is actually fun, even though it's challenging, and you have something to remember. Otherwise, everything is too easy on the lower difficulty levels.