Continuity mistake: Lady Raven arrives at the Coopers' place and starts talking to the wife. Cooper's watch is set to 1:35. An instant cut later it's set to 1:20.
Continuity mistake: At the fancy dinner at the beginning of the movie, Frida uses the titular line ("Blink twice if I am in danger") on Kyle MacLachlan. Rich slightly tips over his glasses as Slater waves his hand. In the next shot, Slater is still waving, but Rich's position is wildly different; his glasses are completely off and in fact below his waistline. (00:09:20)
Revealing mistake: When Professor von Franz (Willem Dafoe) sets fire to Knock's coffin, the flame jets can be seen under the casket.
Factual error: She's driving down the highway, and her car suddenly and immediately dies, with no opportunity to pull off or park. When she gets out of the car, we see it sitting on the bare forest floor - not even a footpath, much less a road. 14. (00:14:30)