A little background: Kimi to, Nami ni Noretara (or Ride Your Wave, which I'll be referring to it as for the rest of this review) is the 2nd anime movie I've seen in theaters and the 1st one that hasn't been a side story for an airing anime. I tried to go into it with only the knowledge that Wikipedia and IMBD gave me, but I attended the movie with a friend of mine who went in totally blind. Based on both of our reactions throughout the film, I'd suggest going in not knowing the "twist" (because if you're good at spotting red flags you can tell what's going to happen at about the ~20-minute mark) that happens 30 minutes in or dragging along someone who doesn't know so you can watch their reaction.
The story isn't particularly revolutionary, but it's good enough to hook you and leave you wanting more. The 1st 30 minutes set up a sweet love story, and then the twist happens and promptly decides to use the beginning of the movie as a baseball bat to beat your heart into submission. The ending can probably be predicted easily, and I kind of wish they went with a less supernatural approach, but I also acknowledge that the climactic ending scene was awesome and couldn't have happened without the supernatural elements so I'm content.
The animation is absolutely gorgeous, and all of the colors are pleasing. Going into the film, I knew that even if the story was subpar that the art would be beautiful, and it did not disappoint. I'd honestly say it's worth seeing for the art and animation alone.
You WILL get the opening song to this movie stuck in your head by the end of it. The OST for Ride Your Wave is good, and there weren't any bad pieces of music. The voice acting was also excellent, and I felt that the cover of the opening song that the two main characters did was so adorable.
I must admit, I never got super attached to any of the characters besides Hinako, but I didn't end up hating anyone. The characters are all competently written and the actions they take make sense. Hinako ended up being my favorite simply because I felt that I'd do the same things she did if I were thrust into a similar situation.
Explaining why I enjoyed this movie so much would have to into the personal and slightly sappy territory, but part of it is the theater experience. Movies are a lot better if you have tons of people with you laughing with or at the movie, regardless of the actual quality. There's just something about stale popcorn and ICEEs...
I thought Ride Your Wave was a very good movie, and I'd recommend it if you're a fan of romance flicks that want to tear your heart out. However, if you're more of an action movie person and can't stand mushy gushy films, then Ride Your Wave probably isn't for you. I hope more people get the chance to enjoy this movie!