Okay, "The Thing with Two Heads" might be bad, and trying to catch the 70 Road Runner and 70 Fury police car in "Brewster McCloud" could cause brain damage if you watch the entire movie.
But then there's "Dr Goldfoot and the Bikini Machine". Is it bad? Oh yes. Do all the beautiful female robots in bikinis make it worth watching? Well only if they were on screen in their bikinis a bit more. But in terms of Mopar continuity, how about Frankie Avalon driving a 65 Fury convertible at 31:00 in the movie and at 31:51 he parks a red 65 Coronet convertible at the curb. Even if a non car person didn't notice the cars were different because of the size difference, the stacked vs. horizontal headlights should have made it obvious it wasn't the same car. For 300 lovers, a 65 300 vert backs into a 65 Dodge 880 wagon at 13:25).