Kimisui banks on the audience’s anticipation on when Yamauchi dies because it’s pre-established that she does die (movie opens with her funeral). The twist takes a different form. There’s also the reveal of the main character’s name. After Yamauchi dies and the MC goes through a cathartic moment, life goes on for him. In Look Back, I kept thinking to myself “oh it’s not over yet?” There are several moments after the “twist” when I thought the movie was going to end already but it kept going (for good reasons) so the emotion you feel is a bit different. Perhaps a bit dull. Maybe you can say Look Back doesn’t have a “climax” in the same way Kimisui does. Also, Kimisui is grounded completely on reality while Look Back has a segment where two timelines converge. So maybe the realism in Kimisui makes it more emotional maybe.