Maps: They are big, very big, reminds me of Diablo 2 Act 3 Kurast Sewer big in Hell difficulty, almost endless corridors.

Enemies: more versatile and WTF than vanilla. Most of the mobs I thought are functioning similar to vanilla's with different skins, until they attack. Got myself killed once or twice.

Dialogues: at least all of the dialogues do refer back to vanilla.

Music: Epic.