Mindless fanservice aside, the episode stayed true to the manga......for the first few minutes, and then the rest they take from elements of later chapters.
Especially with Pandemonium's head. Not to mention that big sinner guy (forgot his name) was killed off earlier. Still the return of Chrno's true form and the sudden appearance of Ewan Remington, as if he's literally flown to San Francisco all the way from New York is amazing. (More on that below.)
Manga spoilers below:
From the manga Ewan Remington (I usually prefer calling him by his first name, sound cooler, but I'd best not confuse people. ) is in fact over 70 years old, and has infused himself with demon cells, giving him demonic powers (which would explain how he can fly all the way from NY to SF in a few minutes) as well as the regenerative powers that keep him youthful. Despite knowing this, I'm still excited by his entrance.