===Story=== Only a handful of independent animators have ever attempted a feature-length film, and it's regrettable that Bill Plympton's first effort isn't more successful. His extremely limited style of animation--he uses about one-third fewer drawings than Saturday morning kidvid shows--worked for his short films, but it simply can't sustain an audience's interest for more than an hour. The limits of the visuals might be less noticeable if the story were more interesting. Del, an aspiring songwriter, needs to come up with a hit in a hurry, so he can marry Didi, a secretary at Mega Music. He visits the weird town of Flooby Nooby where he hears people singing various songs--which he takes and passes off as own. At times, Plympton seems to be trying for the upbeat tone of the old Mickey Rooney-Judy Garland musicals, but those films about "amateurs" relied on very talented professional performers and songwriters. The songs in ''The Tune'' range from amateurish pastiches to utter doggerel. Watching ''The Tune'' is only slightly more entertaining than spending 69 minutes in a sensory deprivation tank. ''--Charles Solomon''