There is no way that Joss Whedon wasn't involved in writing that section.
Gune and his mysterious little doodad:
Gune: Do you know what this is? Neither do I. I made it last night in my sleep. Apparently I used Gindograc; highly unstable. But I put a button on it, yes. I wish to press it but... I'm not sure what'll happen if I do...
Planet... Bob. Helps that it's preceded by a great Gilligan Cut.
Gune and Preed are supposed to be on the lookout for Drej at one point in the movie, but what are they doing instead? Preed is trying to shoot a bug with a cannon while Gune is fiddling with his little bomb.
Gune: Preed! Aren't you supposed to be watching for the Drej!?
Preed: That's right caveman. Drej bad, we good. Now go look at something shiny for a while!
The first thing Cale does once he's accepted the Call to Adventure and is safely on board Korso's ship? Use his new status as the last hope of humanity to try to hit on a very unimpressed Akima.
The cockroach-like cook at the salvage yard complains humans are "unsanitary."
His death is straight up Bloody Hilarious. He's shot by a Drej and reduced to nothing but a glob of green gloop and a pair of dentures (of all things). Even funnier is that the scene is presented in a way that makes it look as though the Drej killed the cook because of how annoying he was.
It gets better: His Last Words ("Bullseye!") are delivered after he is glooped, implying that it didn't even kill him, referencing roaches' repuation for being hard to kill.
Great hilarious line by Gune:
Gune: "Who's your daddy? Gune's your daddy!"
Cale accidentally crashes into the windshield of a starship, and sees a beautiful woman inside the cockpit. He tries to play it cool by producing a rag from a back pocket and nonchalantly cleaning the windshield.