Continuity mistake: When Drake is leaning against the back of the park bench while talking to the tailor, in the shots over his shoulder, his watch is partially covered by his shirt cuff. In the shots from in front, his watch is completely exposed, despite his arm never moving.
Revealing mistake: The footage of the assassin climbing up the drain pipe and leaping across the rooftop at the beginning of the episode is reused from the episode "A Room In The Basement." You can even see Drake already up on the roof from that episode, whereas there's only one person climbing in this one.
Revealing mistake: At Lisbon airport, when Drake and Emma are sitting in the car, the windscreen is rather conspicuously missing, probably removed to facilitate a better camera shot. The missing glass reappears a few scenes later, though, in time for Drake to drive off in the car.