It was fun to revisit Yellow Submarine after so many years. I can remember sitting through it twice in one day during its first release, and it has kept most of its charm to this day.
The plot is a bit of fluff designed to work as many Beatles songs as possible into the movie, and as such, it seems a bit harsh to criticize it for what it was, is, and always will be. Nonetheless, that's the part that doesn't really recall my fondest memories, and when the film is sluggish, that's usually the reason. But the animation is wonderful, and the music, as expected, is the best thing about the movie.
The animation takes a kitchen sink approach, filled with a variety of styles. This work is so lovely, you might miss the fact that it is fairly simple compared to what we get from animation today. "Limited animation" is something I associate with cheap Saturday morning cartoons from Hanna-Barbera, but here, what appears atop the backgrounds is so inventive that you never find yourself thinking of Yogi Bear or Huckleberry Hound. As is perhaps inevitable, many of the songs come across like the music videos that became popular later. Two setpieces in particular are outstanding: "Eleanor Rigby" and "Lucy in the Sky with Diamonds". The latter in particular marvels in its use of rotoscoping. In the use of setpieces, Yellow Submarine is reminiscent of Fantasia.
The music is just as good, even though the soundtrack album has always largely been dismissed. With reason ... that album features two old Beatles tracks and a lot of George Martin's background music for the movie. Because of this, the four new songs get lost in the shuffle, and that's too bad. Paul's "All Together Now" is a trifle, but John's "Hey Bulldog" packs some bite, especially musically. The surprise champion here is George, who contributed two songs, one of which, "It's All Too Much", is among the best he ever put out.
Yellow Submarine is far more than mere nostalgia. If it ran another ten minutes, it would have overstayed its welcome, but as is, it is a welcome addition to the Beatles film output, even if they had little to do with it. It doesn't reach the heights of A Hard Day's Night, but it is a solid #2 among their movies.