Poll: "Hardcore Henry", "Boyhood" and Other 'Gimmick' Movies

Maybe a proper term of designation would be 'concept' or experimentalist movies but this is not meant in a derogatory way, by 'gimmick', I mean one original device that made the film more 'unique' to a certain degree and was used to promote the film. The concept can be defined in one simple sentence and must affect the storytelling process more than the story itself. Now, following the release of Hardcore Henry (2015), which of these gimmicks is the most impressive in your opinion? Discuss here