The Night of the Deadly Blossom - S2-E25
Plot hole: There are two rockets to be launched. The right rocket launches. It is important for the plot for the remaining rocket to explode without being launched. Without explanation, the left rocket just falls off its ramp, lands on the floor and shortly explodes. (00:46:10)
The Night of the Deadly Blossom - S2-E25
Continuity mistake: In the final scene of this episode, the train is shown at twilight. When Gordon leaves the private box car, it is pitch black outside. The last shot of the episode shows the train in twilight again. (00:47:10 - 00:47:45)
The Night of the Deadly Blossom - S2-E25
Continuity mistake: When Barclay hangs the bone hatchet back in its place, the outline on the wall supposedly left by the item differs significantly from the artifact itself. (Most noticeable is the upper end: the outline has one long curled tip, but the actual hatchet has two short prongs there.) The outline was apparently drawn without the prop, or from a different prop altogether. (00:12:05)