An ordinary average earthworm named Earthworm Jim goes about his normal daily life, cruising around avoiding crows and doing other general worm-like things. Until one day, Earthworm Jim is suddenly struck by a very large Ultra-high-tech-indestructible-super-space-cyber-suit. Through sheer luck, Earthworm Jim rests safely in the neck ring of the suit. Suddenly, the ultra-high-tech space particles of the suit begin interacting with Earthworm Jim 's soft wormy flesh. A radical light-speed evolution takes place. Earthworm Jim soon realizes that he is now in control of the suit.
Earthworm Jim 2 on Game Boy Advance features gameplay similar to the first game, with Earthworm Jim running and jumping through levels. There are five new weapons to collect compared to the original game. Characters like Princess What's-Her-Name and Psy-Crow also appear.