When Cliff and Theo are playing chess, Theo never starts the clock to start his turn he just moves and stops the clock.
Not only does the clarinet turn around on the table, but the mouthpiece is on backwards, with the reed side facing the key holes instead of the thumbrest, and it keeps switching from right way to wrong way. (When Cliff puts it on the table, it's thumbrest facing the camera, mouthpiece backwards; but a minute later, it's turned around to show keys facing the camera with the mouthpiece on the correct way; but when Vanessa goes to pick it up, it's back the other way, with the mouthpiece backwards again.)
If I'm not mistaken, Cliff goes up to Vanessa's room at one point, takes the clarinet out of Vanessa's hands and puts it on the table, "thumb rest side" to the camera. Next, it's blurry, but the keys are facing the camera, then the "thumb rest side again"! I know, for I used to play Bflat clarinet and now I play bass clarinet.
Vanessa is in the beginner's class of her band. What music teacher in his right mind assigns beginner students to perform works like "Rhapsody in Blue" by George Gershwin? I wasn't playing that kind of difficult arrangements until I was a senior in high school (which coincidentally, was also in 1984)! These kids should have been playing simple pieces, like Rudy did in Twinkle, Twinkle Little Star.
Many times in this episode it is mentioned how badly Vanessa plays, especially because she doesn't practice unless someone forces her. Why then would her music teacher give her the privilege of performing a solo in her recital? Solos are awarded to students who play WELL. I speak from experience--I played clarinet from age 9 to 24, up until I finished college.
(Clarinet sounds from upstairs)
Cliff: Did we move closer to the river?
Theo: You think she's blowing through the right end?
(Even worse sounds)
Cliff: I think she just killed a goose.
Cliff (catching Rudy twirling Vanessa's clarinet like a baton): What are you doing with that?
Rudy: Vanessa said I could play with it.
Cliff: That's not a toy, it's a goose killer.
Rudy: Do it, Mr. Hampton, do it!
Mr. Hampton: Do what?
Rudy: Make your face blow up!
(Mr. Hampton [Dizzy Gillespie] does his trademark act of inflating his cheeks to twice their size)
Rudy: Can he stay for dinner, Daddy?
Cliff: Can you?
Mr. Hampton: Uh-huh.
Rudy: I want to see him stuff a whole chicken in his mouth!
The role of the man who tries to leave the recital after his child finishes his performance is uncredited.