While Dave goes in the kitchen to talk to Allison, Mr. Bean absentmindedly puts the glass swan on top of the radio so he can check the TV guide. In the first shot of Bean attempting to turn the TV on, the swan is suddenly back on the TV cabinet where it originally was. In the next shot, it is back on the radio.
When the police chases Mr. Bean in the airport, you can see the police run down the side of the floor escalator. In the next shot however, they are leaving the escalator.
When Mr. Bean unintentionally attracts the attention of two police officers at the airport they start to walk over to him. When they reach him one of the officers is different. The two officers then start to chase him and the original officer is back again.
When Bean accidentally launches the glass swan across the room from the stereo, it deflects off the picture and, not only knocks it to the floor, but also puts a large crack in it, just above the middle. However, in the next scene when it falls, the crack is suddenly changed to being on the top edge.
In the first shot of Mr. Bean attempting to turn the TV on, he is fiddling with the garage door remote instead of the radio remote. In the next shot, when Dave and Allison come in the room, Mr. Bean has the radio remote.
The real painting of Whistler's mother is bigger than the one used in the film.
Several spoken references are made to the "Royal National Gallery" as well as the labeling of an exterior shot. It should have been referred to as the "National Gallery" since the gallery was founded by the state, not by royalty.
When the security guard drinks the coffee with the laxative in it, he has to go to the toilet immediately. Laxatives actually take two hours to work.
The remote that Mr. Bean accidentally uses to cause the stereo to launch the glass swan into the picture shouldn't have happened. First of all, the model of stereo depicted doesn't actually come with a remote, and also, the depicted model of remote doesn't work on said stereo. The stereo is made by JVC, and if you look closely at the remote while it's sitting on the coffee table near the TV remote (which was the remote Mr. Bean intended to pick up), you'll notice the Sony logo on the bottom, signifying that the remote only works on a Sony audio system (such as a Sony CDP-CE315). Second, there is no eject button on said model of remote, so therefore, the stereo just happened to magically change music, and the player popped open by itself.
Mr Bean shaves his tongue with an electric shaver, yet does not cut his tongue to ribbons. He similarly drinks water from a hot kettle, yet does not scald his throat. There are hints throughout Mr. Bean (1990) that Bean has superhuman abilities.
In the bar scene, a baseball game is on television. However, in the turkey scene, David says the turkey is for thanksgiving. Thanksgiving happens in November, and the MLB season ends in October.
N.B. This may not be overly significant as November is the succeeding month of October; the turkey may have been bought early in preparation, and will keep if properly stored. It is also possible that the baseball footage they were watching wasn't a live game but a highlight reel.
When Bean tries to dry his trousers using the metal fan during their first meeting at the gallery, Grierson asks him to join their conversation. After Bean turns around, Peter MacNicol is clearly trying not to laugh and almost bursts out right before the scene ends.
You can see Jennifer's mouth move after Bean shakes her in the hospital bed. (She is supposed to be in a "deep sleep").
Near the start of the film, Bean is late for his meeting. In the meeting the boss greets everyone with a "good afternoon" when only just earlier it has shown Bean look at his watch and it was around 9:00 am.
The biker who gave Bean the finger was not wearing a helmet. Motorcycle helmets have been mandatory in California since 1992.
Forty minutes into the film David Langely mistakenly enters his shower while his housemate Mr. Bean is in there already. This doesn't make sense as Langely should have realized Bean was in the shower the second he entered the bathroom as the shower was on and was making the room hot and steamy.
When Bean is standing alone in front of Whistler's Mother for the first time, he places his hands on his hips, which reveals his microphone transmitter.
When Mr. Bean goes to wash his hands in the bathroom, cameras are reflected in one of the mirrors.
Lieutenant Brutus informs David that his daughter was in a motorcycle accident and the two rush to the hospital. One shot of Brutus' police car reveals the camera rig's shadow for a split second.
When Brutus' police car veers at an intersection, there are visible traffic cones and a ladder blocking the end of the street so as not to interfere with filming.
When Mr. Bean is in the operating room, there is a man standing behind a machine who is not dressed like the other surgeons.
The enormous art gallery has only one security guard on the night shift.
Mr Bean is able to sneak into the art gallery at night, without the doors being locked.
Mr Bean was able to enter the control room of The Ride of Doom without a security guard stopping him.
When David fears for his career after seeing the ruined painting, he incorrectly claims that he left Bean alone with the picture. It was in fact Grierson who advised him to stay. David only agreed with him; he didn't actually make the suggestion.
The painting around which the film revolves is referred to universally as "Arrangement in Grey and Black, Portrait Of The Artist's Mother" by art galleries (the first part being Whistler's original title for the painting), not "Portrait of Whistler's Mother".
During Bean's first meeting with David's company, right after he dries his pants and approaches the conference table, you can see Peter MacNicol "corpse" (break character and start to laugh) just before it cuts to a different camera angle.