When Angel is confronted by James at the hotel, James is wearing a leather coat. When Angel is thrown to the right, James' coat disappears. When James starts walking to Angel again, his coat is back.
When Darla stands up from the bar at the end of the episode, you can clearly see the edges of the fake stomach prosthetic she is wearing through her shirt.
In the first flashback of Angelus and James in France, Angelus briefly speaks with his modern-day American accent before reverting to his Irish accent.
In the subway scene, as the train pulls away, Angel's reflection can be seen in the glass of the doors. Similarly, James' reflection is seen in the windows as they accelerate past in the next shot.
After the vampires attacked the college room - and Angel catches up with them - there's a fight between several characters. At one point, a vampire gets throw into the door of a car. After he hits the door, at the tail end you can see Angel suddenly pop in out of nowhere from an editing glitch. It's most noticeable when slowing down frame by frame.