Continuity mistake: At one point, when they time-travel away from "1,000,000 B.C.", Bill is on the left inside the phone booth and Ted is on the right. When the camera switches away, then back, they've changed sides.
Continuity mistake: When Napoleon first comes back from France and he's hanging in the tree, he disappears when the camera angle changes to an aerial view of Bill and Ted.
Continuity mistake: In the beginning, when Bill and Ted are at the Circle K and the phone booth lands with their future selves in it, you hear Bill say "Aw, I hate that part" just as they land in the booth. At the end when we see them land to talk to their past selves, Bill doesn't say that.
Continuity mistake: When the 2 girls at the mall leave after calling Freud a geek, the girl in pink puts her purse strap on her shoulder. In the next shot, it's off her shoulder, and she's seen putting it on it again.
Continuity mistake: During the classroom scene, the spelling of of Genghis Khan's name on the chalkboard changes from "Genghis Khan" to "Ghenghis Khan" between shots. (00:04:50)
Answer: Yes and no. The basic premises are all right; the years are accurate, and maybe the costumes. Napoleon was at war in 1805, and Joan of Arc was undoubtedly in church at some time during 1429, etc. But everything with the mysterious King Henry and his two teenage daughters in the middle ages is completely fabricated. Although there were four King Henrys during that century, none of them fit the age or family situation seen in the film.
Krista