The reason I love Dark Souls so much is that it excels at everything that it does.
Art direction / enemy and boss designs, environmental designs, music (literally the only videogame soundtracks that I actually liked among all game soundtracks), the gameplay itself, the replayability, the truly unique online play, the worldbuilding, the rich and deep lore, even highly memorable lines and voice acting etc.... everything the game does, it does it better than any other game could in my opinion.
Those games are also the only games to truly impact me in any way, and they are the games that made me realize: Games can be art.