Continuity: Don Birman stops at the "A. Bloom" pawn shop. When it is closed, he walks uptown. He passes another pawn shop with a man standing in front of it and we can see the name "A. Bloom" again
Revealing mistakes: When Helen pours whiskey for Don near the end then divides it into two glasses, it is nowhere near a quarter of the way up the glass. When Don chooses not to drink it moments later, and drops his cigarette in the glass, it is more than half-way full.
Continuity: Position of Don's hand changes. This is when Don gets Wick to call Helen after standing her up to meet her parents.
Continuity: Amount of rye in shot glass changes. When bartender Nat pours Don Birnam's first drink, the shot glass is approximately 75% full as seen over bartender's left shoulder. Birnam lifts glass, but does not drink. Cut to camera over Birnam's right shoulder looking at bartender. As Birnam leans away from bar, glass is now filled almost to brim.