Character mistake: When Stan inflates himself, Michael asks, "How'd he do that?", implying that he doesn't know the rules of the Looney Tunes world. Since Michael was rolled into a ball by the aliens earlier in the film, this shouldn't be too much of a surprise.
Character mistake: Game winning shot. The ball is released from Michael's hand and his feet are behind the 3 point line. Toons win by 2, not 1.