I played DeS after DkS, and i have to say, some gameplay elements i liked less, and the game lacked somewhat in content (very few armors and weapons) but the atmosphere is still unmatched, by the other Souls games, for me.
And again, i played it after DkS, so it's not a nostalgia thing.
It's much darker in tone and more oppressive, closer to the darker moments of Berserk (without the extreme gore and rapes, of course).
I would say DeS is more "dark" whereas DkS is more "fantasy", although both fall under the Dark Fantasy umbrella.
