The Night of the Feathered Fury - S2-E17
Revealing mistake: The string used to make the rattlesnake's head move is visible.
The Night of the Tartar - S2-E19
Revealing mistake: When West opens the wall safe in the personal train, there is no locking mechanism shown on the opened door. Without this, the door of the safe could just be opened without rotating the combination lock on the outside. (00:01:50)
The Night of the Vicious Valentine - S2-E20
Revealing mistake: The red-headed villain falls face first into the wedding cake. The front of his face is covered with cake and icing. West "punches" him on the face - but punches are not real - that is why West has no cake or icing on the fist that "punched" the face covered with cake and icing. (00:46:30)
The Night of the Brain - S2-E21
Revealing mistake: Mr. Braine fires a mini-rocket at Brendage, killing him. But a poor camera angle reveals the explosive charge going off in the wall more than two feet to Brendage's left. From the angle at which it was fired, the rocket couldn't possibly have hit him. (00:21:45)
The Night of the Brain - S2-E21
Revealing mistake: Mr. Braine screams as his steam-powered chair crashes into the bandstand. If you look closely at the next shot, just before the explosion, you can see that the dummy now in the chair has its head bowed forward. It also has light brown hair, rather than Mr. Braine's silver hair. (00:47:10)
The Night of the Brain - S2-E21
Revealing mistake: When Gordon is looking outside on their train car platform, it is obvious the background desert scrub is a painted scenery flat.
The Night of the Wolf - S2-E27
Revealing mistake: Though the stock footage is of a real wolf, the animal West wrestles with is too-obviously a dog wearing a fake pair of wolf ears. In later wrestling matches between West and the wolves, the attacking beast is a stuffed prop that never moves its legs, head or jaws at all. (00:03:30)
The Night of the Wolf - S2-E27
Revealing mistake: Talamantes' giant pet spider looks pretty impressive - until it moves and reveals that its wiggling legs are made of rubber. (00:23:30)