This is a perfect helical cycle of time travel, or can say "Each timeline have infinite different parallel space and each space have infinite different timeline". Every time when past change, future become uncertain., this is cycle of past-present and future. Nothing is good than happy ending. How emotions build in a cyborg was amazing.
This movie have best combination of romance, slice of life, emotions, drama, fantasy, sci-fi. If you want to watch sci-fi movie, then I suggest simple rule, just keep your brain at calm, don't jump on conclusion, just enjoy the moment of movie.
The acting of female lead role is strong as compare to male lead role. As told earlier, story hold bind whole characters and also characters good response to story. Some supporting characters are not enough bright like Ai Risa in Jirou's girlfriend role, Kiritani Kenta as Jirou's schoolmate. If directer cast only one of two role, and story focus on his girlfriend or his friend, then I hope it was best. So one star remove only for lack of strong supporting cast.