An abandoned mothership of Sirian origin is sending strange signals from the past, and there's only one man with the guns big enough to investigate Sam "Serious" Stone. If Mental's forces beat Sam to this powerful time-traveling artifact, itís last call for humanity! * Over 40 vibrant levels spread across three time periods: Ancient Rome, Feudal China, and Legendary Atlantis. * A new arsenal of weapons, plus the return of some old favorites. 12 weapons for Sam to choose from in all. * A horde of new, time period specific enemies for Sam to destroy! * For the first time ever, put Sam behind the wheel of three serious vehicles: the Serious Jeep, the Serious Sub, and the Serious Combine! * String kills together to activate a Super Combo Killing Spree. Sam scores higher and moves faster as the body count stacks up. * A new scoring system encourages players to get high scores and earn Gold Medals. Collecting Medals allows players to unlock hidden levels, new features, cheats, and more! * Two player cooperative mode allows friends to play through the whole adventure together. * Play multiplayer deathmatch games via splitscreen or online (PlayStation 2 version only). Up to 8 players can take part in the online insanity!