Revealing mistake: When Aaron is pinned down by the sewer zombie, the zombie actor's neck can be seen below his head mask.
Suggested correction: I went back and watched this scene several times, and I think the OP is mistaking Aaron's hand on the Walker's neck as the gap in the mask.
Continuity mistake: In the scene in the garage near the beginning of the episode where the characters are gathering supplies, the sun is on them in one shot. In the reverse shot, they are dark and the sun is no longer shining into the garage. Then back to them, it is again.