When the bus stops in front of one of the henchmen chasing Frank , the front door opens, but when they cut to the inside of the bus, the door is still closed, and remains closed, until Frank gets up and goes out the rear door.
When Frank leaves the St. Francis and gets on the cable car, it is going towards the end of the line on Market Street, a few blocks away. But in the next scene, the cable car is going uphill in the opposite direction.
When Dr. MacDonald is showing the beaker that supposed to contain the luminous poison, which he just removed from Frank's blood, there is more toxin in the beaker than could possibly have been in a small blood sample; more than Frank could have drunk in the 2 small sips he takes in the bar; more than could have been dissolved in the glass.
Bigelow goes to the doctor complaining of a stomach ache. A toxicologist ran tests showing he was poisoned by luminous toxin. A doctor would not run toxicological tests upon an initial patient visit with a stomach ache complaint.
The majority of the movie is told from Frank Bigelow's perspective, as he recalls events that led him to the police station to report his own murder. When he is in The Fisherman nightclub, a stranger swaps Bigelow's drink for one with a different drink containing poison. But no one, including Bigelow, saw the stranger do this, so Bigelow wouldn't have recalled this detail for the story he tells the police.
After finding out who's in the photo, Bigelow leaves the photography studio and immediately starts getting shot at. He heads toward the factory (screen right) where the shots are supposed to be coming from, but all the shots being fired and ricocheting off the ground, pipe, barrel, etc. are coming from the other direction (screen left).