This is why I love analog, and not just in the sense of "I'm an old fart and old things are better" (though I'm sure there's a good dose of that), but because there's a whole spectrum between "working" and "not working". (Environmental issues aside, that is -- I recognize that the chemicals needed to manufacture and develop traditional film are pretty nasty.) With digital, if it works, it's 100%, which is great, but…
I might be misunderstanding something about cinema projection, but how does a broken lens lead to 20-minute segmentation? The only things I can think of are perhaps it has some sort of cooling mechanism (I know the bulbs do emit massive quantities of heat) that needed a chance to cool off, or they were somehow playing it on a different projector which couldn't handle a full film-reel?
Certainly a more interesting experience than the few glitches I've encountered including "Yes, we know you've been complaining since the 3rd minute of playback that we had the aspect ratio wrong, but we're only going to fix it now, 70% of the way through the film"