When switching to a close up of Triste reaching for the key from Dr. Loveless, its position moves from hanging off his wrist to lying on his wrist. Also, when she first reaches for the key she uses her left hand; but during the close-up it is her right hand that grabs the key.
When switching to a close up of Arte reaching for the envelope in the safety deposit box, it moves position from somewhat folded to almost lying flat.
When Jim is at Tickle's house, Deuce and his boys show up and the start shooting at West. A canister of gas is thrown in the House, by one of Deuce's men. As the room starts to fill with gas, Jim slides toward to Dr. Loveless's uncle. Jim's hat appears on the floor even though during the shooting and several camera shots, there is no hat on the floor. Jim grabs it as he and the uncle get up to leave the house.
During the opening, when West shoots the light and it falls on the carpet, the ensuing fire takes a straight line up the carpet to the table where Dr. Loveless' casket is lying. The only way the flame would move in that manner is if some kind of accelerant were used.
When West and Gordon escape the operating theater, Gordon places an explosive on the wall next to the theater doors. When it explodes, the debris includes major structural beams falling from above. If the explosive had been that powerful, it would have blown the entire wall out as well.
The leather strap holding down James West has almost split in two even before he "cuts" it.
While West is opening Dr. Loveless' safe, Prof. Liebknicht (Michael Dunn) flubs his line. He asks West if he has considered that the files might be filled with "blank newspaper," and then, after realizing his error, goes back and says "blank paper."
When Loveless makes his escape by sliding back through the wall panel in his chair, West tries to chase him. When West hits the now-closed panel he still has a handful of papers that he had taken from Loveless' files. They are supposed to spontaneously combust as a result of a Loveless trick; however, when West drops his hand away from the wall, you can clearly see him holding a lighter of some type that was used to actually start the fire.
Loveless, as surgeon, is given standard latex surgical gloves. The first rubber surgical gloves were made in 1894 and the first disposable latex gloves in 1964. (However, these could simply be yet another of Loveless' man-ahead-of-his-time inventions.)
At 13:16 as the carriage slows to a stop, a hand pulling on some thin wires connected to the horses to get them to stop is visible just to the side of the actor who is supposed to be the only occupant and driver of the carriage. This was obviously one of the horse wranglers riding unseen on the back of the carriage.
Doctor Liebknicht purports to be from Zurich, but his accent is inconsistent. Among the most notable slips is that he sometimes pronounces West's name as it is in English and sometimes as it would be in German ("vest").
When Artie is examining West in the operating room, he states that his spleen is in excellent condition. However, he was checking on the wrong side of West's abdomen. Artie was palpating the spot closer to where the liver is located on his right side. The spleen is located on the left side below the heart.