Plot hole: When Wilbur and Lewis are time traveling for the first time, Lewis says he's done with the memory scanner. Since he said he wouldn't invent Dor-15, and she went away, wouldn't the time machine and everything else in the future go away since the memory scanner started it all and Lewis decided to quit?
Suggested correction: Lewis wasn't fully giving up. He was just frustrated and probably went back to it later anyway. Whereas with Doris, he deliberately decided not to invent her because of the danger she posed.
Other mistake: In the beginning of the film when Lewis is dropped off at the orphanage there is a blue car parked in the background. This is the same exact car (license plate and all) that he is driven away in when adopted at the end.
Suggested correction: There are 3 options: First, it may be a car that hasn't been sold to their future owners (Bud and Lucille) since it was still in the past anyway. Second, if it is proven to be Bud and Lucille's during this time, it could still make sense, as we could see in the ending when Lewis tests his memory scanner that Mildred (or the orphanage lady) was present in their wedding. Third, it's also possible that it's just the default model for the car and we weren't supposed to see it.
