King orders a vodka and coke in the hotel bar and when you see him drinking it there is no coke in the drink.
There's more Coke in the bottle that was spilled, later.
In his narration, Michael Caine claims that five people were in their graves, as a result of the proceedings of the movie, but there were actually six: Preston Gilbert; the singer at Preston's banquet; the accordionist at the banquet; the servant at the poolside shooting ("the projectionist," according to Nadia Cassini); the old Italian who directed Caine to the beach; and of course, Jack Miller.
When Mickey Rooney is singing Italian songs with a band at an outside banquet, the band calls out for "Sorrento...Torn'a Sorrento." Rooney accedes --- "OK, let's go back to Sorrento," whereupon the band and he break into a rendition of "Santa Lucia" instead !.
Miller is identified as a lecturer at Berkeley University. There is no such school; clearly Hodges meant the University of California at Berkeley, normally identified as "UC Berkeley."
In the tour group scene as Mickey and Liz get into the car with Dinuccio, the overhead boom mic is clearly visible in reflections on the car.