In the hospital scene with Paul, Longbow and McCabe, there is not a single piece of medical equipment in the room. There's a bed, a chair and a privacy curtain. That's it. There isn't even one of those tables that slides across the bed.
When Johnny is in the x-ray room explaining the mythology, he is obviously reading his lines, as one can see his eyes moving back and forth line by line.
Midway through the movie, when Paul is suffering from the Moon Beast illness, the camera zooms in on an obvious photo of the full moon.
When Jeanne Swain's character, Caroline Harris, watches TV and drinks a Coors beer while her drunk husband returns home from bowling, the cigarette she takes two drags from and extinguishes in the ashtray is unlit the entire time.
While Johnny Longbow and his students are watching the meteor shower he can be clearly seen saying something but the audio for the line is never heard.