I did act 1 pretty thoroughly, then focused on the campaign and watched all the cutscenes. It was beautiful work by the developers. I got into nightmare dungeons this weekend. I might try to get past the t3 capstone dungeon tomorrow afternoon to push into the highest difficulty. I bet I could right now, but I read optimal leveling is no more than 3 levels above character level. I hit a nightmare dungeon that was 8 above me and wasn't at all impressed, so I'll just believe that and work with it. I'm having a great time though.