This game is so good, it made me want to wipe my own memory and play it again. No game I've played ever came close to the immersion and detail of this world, and It's not possible to explain how amazing it is in a review.
Playing this game made all other games look like actual trash, that's how good it is.
One warning though - once you started playing, you can't stop, doesn't matter if you have school, work, or whatever, this game will take over your life for at least a month, don't say I didn't warn you.
I hope I can enjoy a game like I enjoyed this one, its an amazing experience.

Edit: I have over 400 hours on this game spread on different accounts, not just 40.