I don't think a movie needs to have a twist but it does need a single moment that rises above the rest. Often this is the last moment, but it doesn't need to be: "I'm done" in There Will Be Blood, the dad lamb in Lamb, the Bellagio fountains in Ocean's 11, the spider in Enemy, Nicole Kidman's last line in Eyes Wide Shut, "Welcome to the Planet" in Man of Steel. It's a release, it discharges any energy the film left you with or purposefully built up - I think this is an important part of leaving the audience satisfied. It can be a simple button that is inconsequential, but something that provides a moment of catharsis either for the experience the audience just went on (which could very well be totally separate from that of the characters), or a collective catharsis for the characters and the audience who are along for the same ride.