Continuity mistake: Willow's hair changes position between shots when the vampire brushes her hair back and kisses her.
Continuity mistake: Whenever we see the two Willows together in this episode we see that Vampire Willow is understandably very pale in comparison to the living Willow. However, in the library with Cordelia, when Vampire Willow says 'How about dinner?' her face is no longer pale.
Answer: She has superpowers, ergo fast movement. The reason she outruns him so easily in "Touched" is that she stops trying to actually fight him and just dodges instead.
Shay