I rarely write reviews for movies but I simply have to recommend this one and straighten a few things out. First off let me say that this is my top 3 favorite films from Ghibli Studio (the other two being Castle in the Sky, and My Neighbor Totoro). The reason I love it is because out of all the great Ghibli works, this one speaks to me the most. And the more I watch this film and the older I get, the more I appreciate it.
It's a shame that this little gem is often underrated, under-appreciated and neglected by Ghibli fans, because it's so not like anything Ghibli or Miyazaki has done so far (which, ironically, is one of the reasons why I love it so much). It doesn't follow the usual Miyazaki formula (i.e. brave and independent heroine, epic stories, unusual adventures...you get the picture). Instead, it just tells a simple (yet highly-effective) coming-of-age story about an ordinary high school teenager in a realistic and sincere way. You may not have the similar experience as the male protagonist, but you can certainly relate to him and understand what he's going through (at least I could).
Now it seems that the complaints from those who were less impressed by this film are mostly centered around the film's (seemingly) lack of a solid plot or exciting actions. To them I'd say you people just didn't get it. As some reviewers have said, this film is all about the subtleties. It's more of a character-driven film than a plot-driven one. In other words, it's more about how you feel about/relate to the characters (dialogs, emotions, relationships, etc) than what you see on screen (the plot, actions, stunning visuals, etc). The thing is you can't just watch the movie, you have to "feel" the movie and its characters as well. And it helps a great deal too if you also know a thing or two about the Japanese culture and life in small town there.
Truth to be told I never really enjoyed all those Miyazaki extravaganzas such as Princess Mononoke, Spirited Away or Howl's Moving Castle, which of course isn't to say that they are not great. Don't get me wrong, I can see why they are great masterpieces and why people would love them, but personally I just couldn't connect with any of those movies nor can I relate to the characters. I always felt I was merely watching the movie, instead of "experiencing" it. But with "The Ocean Waves/Umi Ga Kikoeru", I felt like I was the main character and his story was my story. For some reason this movie just speaks to me like no other Ghibli movies can. It might be an animated TV movie, but to me it felt more real than most of the live-action TV dramas out there, because everything shown in that movie seems so realistic and familiar and therefore gives you a similar warm and nostalgic feeling that you also get while watching movies like My Neighbor Totoro. I've heard it said that it's the small things in life that make living wonderful (or something like that), and I think this best describes how I feel about "Umi ga Kikoeru".
If you're into big epic/fantasy movies like Spirited Away or Howl's Moving Castle, chances are you probably won't like this one. At the end it really all comes down to whether you get this film or not. If you get it, you'll love it!