Revealing mistake: When Elly is "skating" on the black oil while fighting the bad guys, we can see that it is Bryce Dallas Howard's stunt double in a few shots where it briefly shows her face.
Revealing mistake: During every flashback of the altercation leading to the homicide, the beer bottle completely shatters from just a touch like a sugar glass movie prop. The first time we see the flashback, it is also clear that the minute pieces fall off the table in the first shot, but in the reverse angle, the bottom of a broken bottle is resting on the table.