This platform adventure game finds Jimmy returning from outer space - with an alien life-form stowaway. The alien starts cuddly and cute, but quickly becomes a ferocious beast with a voracious appetite for destruction. Once again Jimmy Neutron must use a revolutionary invention system to create some inspired gadgets to capture and contain the quickly multiplying alien attack.
Players are able to create over 26 gizmos, 11 inventions, and four super inventions. There are of course also secret gizmos hidden in each level to give Jimmy Neutron enhanced power-ups. With the help of these gadgets, Jimmy makes his way through six episodes spanning 15 levels including Jimmy's Lab, Twonkus-3, The Neighborhood, Downtown, Retroland and the Final Showdown.