Chief Bobnar shaves his stubble with a beetle. Parts of his stubble reappear during his conversation with Dug.
As Dug falls down the stadium seating, Hognob looks at his wrist to tell time even though he isn't wearing a wrist watch. That may seem like a goof, especially considering that wrist watches weren't invented yet at the time the movie takes place, but that's the point of the joke. It's to imply that Hognob is realizing that Dug is taking an awfully long time to fall to the bottom of the stadium.
The first scene takes place in the Pleistocene, but two dinosaurs are present. The last non-avian dinosaurs died 65 million years before that time.
Lord Nooth wants to remove Goona from the field for being a girl, despite the team of primitives already consisting of several women. What he should have done is remove her for not being a primitive at all, since the match was supposed to be Real Bronzio vs the primitives.