Gaffes

When Neil spills the whiskey into the sink, the contents of the sink look different between the close-up and long shots.

After his jump off the bridge, Neil finds himself on a bench with his dog. Despite being completely soaked moments before, Neil is fully dry. He also calls Catherine with his cell phone, which would not be working after being completely soaked.

Neil knocks a nearly empty bottle of Lemon 'Fairy Liquid' into the sink. In the next shot it is back on the window sill.

When Neil looks at the depressing weather outside his window and commands, "Weather, be like it is in Los Angeles," it becomes nighttime, annoying him. But weather and time of day are two unrelated attributes, so the time of day should not have changed.

The U.S. Army uniform Grant wears has shoulder boards of infantry and pinned branch insignia of military intelligence. He would have to be one branch or the other not both.

The Pioneer probe is depicted flying with its parabolic dish pointing forward. Obviously, in reality this dish was pointing towards Earth at all times, which would not be in the direction of travel by the time of the Saturn encounter.

Although the introducing narration is correct in that the Pioneer launch-vehicle was a Titan III-Centaur, the footage shows the Saturn-V, the launch vehicle used for the Apollo and Skylab missions.

This fact is noted in the closing credits.

As Pioneer 11 passes Saturn, its route clearly intersects the shadow which the planet is casting on its rings, yet the probe remains illuminated by the sun.

The human skeleton that lands at the feet of the headmaster after coming to life and jumping through the window is obviously not the same one that was used in the classroom scene. When the headmaster holds it the joints are obviously molded, and it appears to have no weight. It is obviously a lightweight plastic model.

In the opening credits, the members of Monty Python are announced as: "The intergalatic council of superior beings". The word "intergalactic" is misspelled.

One of the council members criticises the lesser alien races for always being naked on their probes but as they themselves are naked they should not find this worthy of comment.

In several scenes the audio is clearly dubbed. Dialogue spoken does not match mouth movements.

Neil bestows speech on the skeleton, then tells it to jump out the window. When it lands, it is no longer sentient, though Neil did not explicitly undo the command.

If Neil wanted Dennis to stop talking, he could've easily used his power to do so.

When Neil tries to catch up to Catherine down the street, he could've have easily used his power to either appear in front of her or to make her appear in front of him.

The Boom Mic is reflected on the kitchen window when Dennis talks about dogs having their tummies tickled.

Neil wishes himself a great body. Later, he appears shirtless with his regular body.

Near the very end, when Neil tries to demonstrate to Catherine that he no longer has absolute power, one of his proofs is him waving his hand and saying, "Us be on the prow of the Titanic." If he had been wrong (e.g., if just a delay in his powers had developed), he would have killed them both, since, considering the way his power often worked, he would have sent them to the Titanic, over two miles under water, and the pressure would have crushed them instantly, before he could do anything.