Continuity mistake: As Gilligan marches over the cliff, he's wearing Skipper's hat. As he's hanging on the branch, his regular white hat is on his head.
How Green Was My Grass - S4-E24
Continuity mistake: Before this episode (and after as well) Darrin and Samantha give their address as 1164 Morning Glory Circle, however in this episode, when Darrin slams the door, the '9' in 192 on their address spins around to make 162, hence the angry neighbor at 162 saying that his grass was installed at the Stevens' by mistake.
Continuity mistake: When Scott is in the cockpit of the Mole, he has two blue tubes in the holsters of his belt. But when he is cutting through the fire doors, the tubes have changed to one blue and one yellow.
Continuity mistake: After Herman breaks through the doors in the opening sequence, the underlying wood over the right side of the hole is plain plywood. When it's Lily's turn to come out, the wood has been stained to match the rest of the door, and Herman's outline is more distinct.
Morticia and the Psychiatrist - S1-E2
Continuity mistake: When Morticia is watching Gomez and the trains, at the second of the collision and explosion, it's a re-use of the shot when Mr. Hilliard is there, as in just a split second, you can see him, then there's Morticia again.
Emergency Marineville - S1-E11
Continuity mistake: When the second group of Spearhead jets take off from Marineville there are only two jets, but in the next shot you can see three jets, and in the next shot there are two again.
Continuity mistake: Bud is lying on a surf board, talking to Flipper. During different camera angles, his position on the board changes. He goes from the middle to almost the top. At the end of the scene, in the wide-shot, he's always to the end of the board. He also goes from being centered with a foot on each side of the board to being on the left-side with just that foot in the water. (00:13:20 - 00:14:20)