Character mistake: When Death is playing hopscotch by himself he says "best 75 out of 81." But it would be best 75 out of 149.
Character mistake: The Rufus hologram states that he first brought the phone booth to the Chosen Ones (Bill and Ted) in 1989, referencing events of the original film. While that was the year the first movie came out, it took place in 1988 (indicated by the opening title card and dialogue throughout the movie).
Factual error: Babe Ruth is shown batting right-handed; in reality, he batted left-handed.
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.
Plot hole: At the end, everyone was returned to their own timeline. Except for Ted's dad. He's shown still playing till the end and not disappearing like the others. However, this version of Ted's dad came from the future when he attempted to arrest his son at David Grohl's house. Therefore, he should have disappeared with the others and returned to his future timeline.
Suggested correction: That's not what happened at the end at all. Only those whose were time-displaced returned to their own timeline. Which is why we see Kid Cudi leave, he was time-displaced and not picked up in the time machine. You can even see Ling Lun is still playing.
Incorrect. Ted's dad was time displaced as well. He never arrived by the time machine, but was sent to hell after being killed by Dennis. Therefore, he should have been sent back to his future timeline.
Ted's dad was never time-displaced, nor did I say he arrived by time-machine. He was sent to Hell in his own time line and then went with the group to 2020. Unlike Kid Cudi who was time-displaced because he popped out of his own timeline because of time and space collapsing. Just being from a different time isn't what time-displaced meant.
Factual error: Jimi Hendrix and Mozart are depicted as being roughly the same height, when in fact Mozart was 5'4" and Hendrix was 5'11."