Final answer:
The E! Online review identifies that 'Ice Age: The Meltdown' lacks insight and intellectual depth, which is the film's performance gap.
Step-by-step explanation:
The performance gap identified in the E! Online review of Ice Age: The Meltdown suggests that the film lacks depth compared to Pixar films that are known for having both insight and intellect. The review mentions that the sequel provides plenty of humor to entertain children and prevent adults from boredom through funny gags, although some catchphrases might be seen as cringe-inducing. However, the saving grace of the film, according to the reviewer, is the character Scrat, whose acrobatic antics and kung-fu moves standout, offering excitement much like impressive special effects in movies that otherwise may have unoriginal plots and subpar acting.