Continuity mistake: In the beginning of the movie when Debbie visits Danny's grave she is standing and there is no bench. At the end of the film she goes back to visit Danny's grave and a bench magically appears which Debbie is sitting on and mixing a martini.
Factual error: A shot of Paul Damanian's computer's screen shows mostly a large wallpaper. At the bottom, there is a taskbar that resembles that of Windows 10. Judging from the task view icon, it is Windows 10 version 1709 or earlier. The taskbar is retouched: The Start button is missing, and the Microsoft Store icon is edited to have the Windows logo cropped out. The taskbar is missing the clock, and the Action Center icon appears before that of the Touch Keyboard icon. There are four icons on the desktop, but none have a label. The icons correspond to "This PC", "Contacts", "Documents" and "Pictures" but none are genuine Windows 10 icons. The "This PC" icon is from Windows 7, while the other three icons are edited versions of what's seen in Windows 10. There is a battery icon but this item appears on laptop computers only; this one is a Dell desktop computer. After clicking on the Search icon (Cortana seems to have been disabled) a task manager appears instead. Moreover, the task manager belongs macOS rather than Windows. No wonder the tasks shown in it moments later are running in the context of the "root" user account. Then an app is executed on that computer called "McCallister Security Visual Matrix Controller 184.108.40.206" but the window chrome indicates that it is a Linux app. (00:48:25 - 00:48:55)FleetCommand
Factual error: This film repeats on of the classic mistakes that countless films have repeated since the invention of personal computers: It shows that letters in a password are discovered independent of each other. In reality, this is not possible. The computers themselves don't know the password; they only know a "hash digest" with which they can only determine if the password is 100% correct, or not. (If you need technical details, look up "Cryptographic hash function" on Wikipedia).FleetCommand