The style of the art is terrific; it was unlike anything in animation at the time, but was much imitated afterward. I always thought psychedelic artist Peter Max was inspired by it, but many people believed the reverse; Wikipedia tells us:
The animation of Yellow Submarine has sometimes falsely been attributed to the famous psychedelic pop art artist of the era, Peter Max; but the film's art director was Heinz Edelmann. Edelmann, along with his contemporary Milton Glaser, pioneered the psychedelic style for which Max would later become famous, but according to Edelmann and producer Al Brodax, as quoted in the book Inside the Yellow Submarine by Hieronimus and Cortner, Max had nothing to do with the production of Yellow Submarine.
I was a Beatles fan in my youth---although they'd long broken up when I got into them---so I enjoyed the music. The dialogue was full of puns, which I liked, and I often think of the insanely imaginative scenes in the movie. When I've been through any difficult time and am asked about it, I have to urge to describe it as "'Arrowing," plucking arrows from myself (as happened to Ringo in the Sea of Monsters). (I suspect Rick Riordan got the title for the second Percy Jackson novel from the film's Sea of Monsters, by the way.)
It's loaded with neat ideas, like the various seas, which are bizarre in very different ways (Time, Science, Holes, Monsters, Green), and has a lot of fun with the public perceptions of the individual Beatles---Paul comes out of a room where all the women are cheering and throwing flowers, for example. The side characters are great, including Jeremy, the crazed Chief Blue Meanie, Max, and the Mayor. Naturally I loved that the captain of the submarine was named Fred, even if he couldn't make his soap float. The various forces of the Blue Meanies were distinct and nefarious, including the Apple Bonkers, Storm Bloopers, Countdown Clowns, Butterfly Stompers, and of course the Dreaded Flying Glove (shudder).
But I have some small quibbles and one huge objection, and the huge objection has rendered it unwatchable for me. Spoilers ahead, as they say.
1) Ringo is Billy Shears, damn it. When, during the climactic concert, Billy Shears is introduced (at the beginning of "With a Little Help from My Friends"), John takes off his Sgt. Pepper disguise to start singing. What the hell? Ringo is the heart of the movie; it would have been perfectly in character. Still sore about that.
2) Real-life Liverpool is painted as a terrible, depressing place at the beginning of the movie (complete with "Eleanor Rigby"), but Ringo's friends live in a weird, fantasy building full of wonders and delights. Not so bad after all, is it? Seemed too much like the magic worlds waiting on the voyage ahead.
I recent heard columnist Jonah Goldberg say on a podcast that gun culture is one place where movies are conservative: "I've yet to see an action movie where the protagonist... vanquishes the enemy with a wonderful poem about peace." Well, Mr. Goldberg, I do know of such a movie, and this is it. And now it is a problem for me.
Like a lot of young idiots, I once thought that our parents were dim bulbs about confrontation and violence, that reacting to violence with violence only perpetuated violence. War was never the answer. In this movie, the Beatles and their allies are victorious with the twin powers of music and love. In the end everyone becomes friends. Why, the Chief Blue Meanie even admits that his cousin is the Bluebird of Happiness!
This works great, provided your enemies hate love and "shrink from the sound" of music, the way the Meanies do. Then love and music work well, but not because they're so awesome, but because they become weapons. I enjoyed the ultimate battle of John vs. the Dreaded Flying Glove (to the wonderful poem set to music, "All You Need Is Love"), but nothing in life has ever led us to believe love would do anything against humans who want to kill other humans. Nonviolence works fine against people unwilling to commit mass atrocities, but oh so many people are. And I reiterate that the Beatles won the battle because to their enemies, love and music were the equivalent of violence.
So the film's message has lost all resonance with me, especially after September 11, 2001, when we Americans got an education in how much others really want to kill, how little they care for our most sincere overtures of friendship, how little love they have for anything beyond tribal affiliations. The Taliban does despise music, but sadly they do not get knocked senseless by it---they just ban it and jail musicians.
It is not that the movie is not entertaining; it's that the lessons it wants to teach are foolish. It tried to lift more weight than it was capable of bearing. For much too long, I believed it could, too. You can say "It's just a cartoon, for Pete's sake! Lighten up!" But the Beatles were serious, or wanted to be taken seriously, with the antiwar "All You Need Is Love" stuff, and I respect the filmmakers enough to believe they were too.