Continuity mistake: When Lloyd drops Mary off at the airport and hugs her goodbye, in the background there are two men walking towards them. The camera changes to the angle behind Mary then behind Lloyd and then back to the side. When it returns to the side view the two men are farther away but still walking toward them.
Continuity mistake: When Harry and Mary go out on the date to the ski resort, when they get into a snowball fight, the camera shows Harry, and it's snowing, but when they show Mary (who is supposed to be right beside him) it is not snowing. It keeps doing that, when it shows Harry it's snowing, and Mary it is not (or vice versa).
Continuity mistake: After leaving the diner, Lloyd & Harry are pulled over by a motorcyle cop (Harland Williams). As the cop notices the beer bottles on the floor of the van, you'll notice his hair has a curl hanging over his forehead. Right before he takes a drink of one of the bottles, the curl is gone. It cuts to Lloyd & Harry trying for a brief second , and when it cuts back to the cop saying "You'd shut your mouth if you knew what was good for ya," the curl is back.
Continuity mistake: When the "gas man" falls to the floor due to the atomic peppers that Harry and Lloyd sneaked into his burger, Harry and Lloyd laugh at him, and Lloyd even points at him. Then he stops pointing at him and looks at Harry. But only a moment later, in the very beginning of the next shot (a close-up of Harry and Lloyd), Lloyd is instantly pointing again.
Other mistake: In the brief scene in which Nicholas Andre and J.P. Shay are talking about the killing of the owl at the preservation society ball, if you look very closely out the very bottom of the window, at the very end of the short scene (right after Andre says, "Their guys aren't just anybody, they're good"), you can catch a brief glimpse of part of the box containing the victim who is trying to escape (this box was completely excluded from the film).
Continuity mistake: After Harry and Lloyd start gagging over the atomic peppers, we see a brief shot in which everyone else in the restaurant looks at them (and the waitress suddenly appears in that shot as well). But in very the next shot (back to Harry and Lloyd, still gagging), nobody is looking at them (and the waitress, who was there just a moment ago, disappears).
Revealing mistake: The Aspen lift operators are wearing Copper Mountain uniforms. Copper Mountain is in Colorado, but it is over two hours away from Aspen.