Continuity mistake: When the episode starts Arya is walking towards where Daenerys is and has her face covered in mud and soot, plus a long streak of dark dry blood running through the right side of her face. The next time we see her her face is cleaner and the blood is less noticeable. In further shots the amount of blood increases or decreases randomly. There doesn't seem to be much water and soap around the place.
Continuity mistake: When Hook comes to see Emma at the sheriff's station, his earring disappears when she kisses him goodbye.
Continuity mistake: This is supposed to be the Rangers' first mission and we see Jayden use the Fire-Smasher mode of his spin sword. Jayden didn't learn how to use that feature until the third episode of the series, which takes place after this mission.