Revealing mistake: While Poe leads the aerial assault on the oscillator, in the closeups of Poe and other X-wing fighter pilots, note the cockpit windows at the pilots' left and right have identical marks and scratches in their individual X-wings. It's particularly noticeable when one closeup follows another.Super Grover
Other mistake: When Marry Anne flies into the dark forest for the first time she drops the boutonniere. After seeing the primrose petal she flies off empty handed but has the boutonniere later when she meets Roland.
Continuity mistake: In order for Superman, Wonder Woman and Batman to break into the secret room, they knock it down. Four enemies who were waiting for them in front of the door are crushed by the falling door and blood is splattered, forming a pool of blood in front of the door. During the fight that follows, there are several shots where the knocked over door is shown, but the pool of blood at the front of the door has vanished. (00:07:10)Casual Person