Deliberate mistake: When Mr. Roboto is offering Austin a mushroom, the subtitles lead Austin to think Mr. Roboto is asking him to eat some shit, until Foxy reveals more of the subtitles to say "Please eat some shitake mushrooms." The correct spelling for this kind of mushroom is "shiitake." They had to cheat on the spelling in order to make the joke work.
Continuity mistake: The plate of asparagus in the fountain room is not seen when Austin first enters the room. When Austin plugs the fountain back in, the plate disappears.
Continuity mistake: When Austin and Foxy are in the time machine leaving the club about to travel to 2002, Foxy is wearing large gold hoop earrings, but after the first shot she only has one earring in (the left ear).
Continuity mistake: When Austin kicks Mini Me, the knife and envelope are dropped under him. Two shots later, the knife is still there but the envelope has vanished.
Other mistake: Right as Austin performs "Daddy Wasn't There", the camera moves in on the band and people move out of its way. One of the extras on the left side quickly looks right at the camera and realises she needs to move.
Answer: The footage of Michael Caine is from the 1967 film Hurry Sundown.
David Mercier