When Lucy enters the outpost, she passes the mirror and closes the button on her dress. However when she turns back to the table and sits down the button is open again. Then when she stands close to the wall during the attack, the button is closed again.
When Priest readies himself to leave the city, his hands change from being wrapped to unwrapped then back to wrapped when he gets his motorcycle.
In many scenes, the cross on Priest's face, which is supposed to be a tattoo, is wiped off from the end of his nose and reappears as a full cross. One of the most noticeable moments in a short time span is at the Nightshade Reservation. Priest has one of the familiars pinned to the ground and when the camera focuses on his face, the end of the cross has been wiped off. Camera switches back to the familiar who points to the sky and when Priest turns to face the sun, the cross is fully drawn on again.
Near the end of the movie when the trio is planning to head out after the train and destroy it. The male Priest says "I will start charging the bikes", meaning they were electric. A few minutes later they reach the train and the female priest gets chased by other motorcycles and she hist a button marked 'Nitro'. Nitro is for gas powered motors. (However, when seen from the side, the female priest's motorcycle has three cylinder heads, meaning there's a 6 cylinder engine, which may be the one getting the Nitro boost.)
When the town of Jericho is attacked, a record playing Mozart's Requiem is playing. Specifically, it is at the movement called "Tuba Mirum". When the attack itself begins the vinyl record skips forward and the "Dies Irae" music plays. While an effective moment in the film, if a record skipped forward from the Tuba Mirum it would not land on the Dies Irae (the latter comes before the former on a disk).