Continuity mistake: After the waiter has delivered tea to Quackie and the mysterious man, you can see the wall outside the carriage is coloured pink. But when we see a close-up of someone putting the ingredients of a pill inside a cup, the wall is now coloured brown.
Continuity mistake: When Quackie is hit on the head by a club at the Club Car in the train, he stands outside the car and you can see the words "Club Car" on the door. In the next shot, the words have gone.
Continuity mistake: When Quackie catches up with the mysterious man at the railway station, he walks up to the carriage of the train and you can see there is nothing on the carriage, but in the next shot writing appears.