Other mistake: The van used by Cecilia to chase Tom should be damaged because of the crash, but it was not.
Other mistake: When the protagonist is making the exchange via the BMW and tries to slip the Algorithm into the passing car (himself), the window of the car is up, so there's no way he could have thrown it in. (01:19:55 - 01:33:55)
Other mistake: When Gary is about to test the trap check the bus door on the right: there's a reflection of what seems to be his shirt, but it's a long sleeved wrinkled shirt, not the short sleeved he's wearing. What's even more bizarre: when Gary moves around, the reflection stays completely still and, drumroll, a shot later, from the very same angle, the reflection disappears. Either it was a crew member hiding, or a CGI-made reflection placed to hide some unwanted crew or equipment reflection.
Other mistake: In the credits of the movie, the creator of the original comic's name is misspelled as "Bob Macleod" when it should read "Bob McLeod."
Other mistake: At the end, when Bill and Ted reunite with their wives, one of them mentioned hearing Ted say something about distributing instruments to everyone throughout all time. However, Ted said this a minute or 2 before they arrived. We even see the phonebooth they are in land after the statement was made. Therefore, there was no way for his wife to hear him say that.
Other mistake: In the frame you can see the girl is playing on a newer Macbook, she is using a wired headset but the headset is not plugged into the laptop, you can also see she is using a wired gaming mouse, and the USB cable is just sitting there not connected to anything. The Macbook is USB-C only and the mouse is USB-A.
Other mistake: Isaac was able to break through his wrist restraints (taped to arms of a chair), escape two androids, quickly find and escape with Sara (while other androids started pursuing) - during a "full security lockdown" in a facility previously unknown to him. Isaac would not know the building's layout or where doors - and an exit - would be, but he had little problem getting out during lockdown while numerous people and androids were chasing him.
Other mistake: The way Katelyn exploded was described by Mara as being like a balloon popping. Every time a student exploded, blobs of blood (and tiny pieces of the body) splattered everywhere, making a huge bloody mess. When more than one student exploded going down the stairs, blood looked like it was being poured from a bucket. Sometimes, parts of clothing could be saturated in blood (such as a sleeve), but there was always more blood splattered nearby. When Katelyn was at the doctor's office (to get a piece of someone's bone removed from her forehead), "blood" goes smoothly/evenly around her eye to the lashes with no gaps or splatter marks. Blood from an explosion would not fall this "perfectly" around eyes. For example, folds in the eyelids would block some blood from landing in certain places and eyelashes should have some blood on them but Mara's did not. (01:41:27)
Other mistake: The time freeze dome extends well beyond the little Italian square and covers the surrounding buildings as well. Everybody and everything is paralyzed/suspended, but a gramophone in a window looking directly at the square continues to play. (00:34:03)
Other mistake: When the kid first leaves and enters the house, he takes out the crossbow with an arrow in it but the elastic drawstring is flapping around in front. (00:22:33)
Other mistake: "Sally" the Great White Shark rammed Emma into a rock (or other hard object) underwater and Emma only got a small cut above her right elbow. It isn't clear how fast Sally was swimming, but Emma was rammed with force (and appeared to hit her back). A female Great White Shark weighs about 4,000 or 5,000 pounds, so Emma would be expected to suffer a major (not minor) injury under the circumstances. (00:05:24)