Sorry for commenting on such an old game. I recently found it out and I can say I really loved it. I have a question about the all diffculty extra. Is it more lore?
No need to be sorry! In fact, I'm glad you left it! The area you unlock after effectively 100%ing the game is not extra lore, it's more of an easter egg and a way of congratulating players for seeing everything the game has to offer.