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: When Cassandra hits the ambulance brakes, skid marks from previous takes are perfectly visible.
Revealing mistake: We see Caesar's Palace in 1966. There are 1970s and 1980s cars in the driveway.