Goofs

When Constable Matson comes to talk to Kochek in his store, Matson has his cigar in his mouth. In the next shot, he's holding it in his hand.

When the monster is trying to break through the steel door at the top of the lighthouse, it is a single door. But when he breaks through, it is a double door.

This goof report is a mistake. The camera angle doesn't let the viewer see the other half of the double door when the monster is trying to break through. It's clearly a double door viewed fro the outside. If you carefully look, you can barely see the other half of the door when the monster is pushing on it.

At 109 Fred throws a clothesline up to Sturges, the Lighthouse Keeper. The working end of the line is about one foot long, swings loosely and wraps halfway around the post. After Sturges is thrown off the lighthouse Fred appears at the railing. The working end of the line is now about 3 feet long, wraps around the standing line, and appears to loop once around the post.

The "meat cleaver" covered in the monster's blood can clearly be seen to be a prop made from painted wood even in close-up shots.

At 1 hour 10 minutes the monster is knocked over the railing and plunges into the sea. Impossible. In the first minute of the movie there are various distance shots of the lighthouse that clearly show the lighthouse is not located at the water's edge.

At 41 minutes in, Doc and the Constable park the jeep in town. As they get out, a boom mic - and the crew member holding it - is clearly reflected in a store window behind them and follows them as they move out of the scene. It is not at the top of the screen, and couldn't be cropped out.