In 'Lab Rumble Showdown', players step into the shoes of a reluctant lab technician who's inadvertently become the star of an underground cage-fighting circuit. Each fight takes place in a different eccentric scientist's lab, filled with bizarre inventions and creatures that come alive during the battles. Players must navigate through a series of increasingly bizarre challenges and combat scenarios, using their understanding of science and quick wit to survive and win. The outcome of each fight shapes the storyline, with choices impacting everything from alliances with quirky lab assistants to unlocking powerful experimental upgrades for the next match.