The Night of the Bubbling Death - S3-E1
Revealing mistake: As West drags the body of a bad guy out of the scene, the supposedly unconscious man is holding his head up so as not to have his head dragged through the dirt. A truly unconscious person's head would flop back on to the ground.
Revealing mistake: When Ultraman finally confronts the fake Ultraman (Zarab), one of the shots shows the two Ultramans rotating around, followed by a right-hand punch right to the fake's left neck. At the end of the shot, the suit actor can be seen wagging his right arm in mid-air, possibly hitting the neck too hard. What's even noticeable is that parts of the silver paint on the right glove fall off. (00:23:34)