A sci-fi action game, SPG puts you behind the wheels of a "Gunbike", a cybernetic motorcycle that can change into a robotic power-armor and an all-terrain buggy.
Your objective in the game is to give chase to several evil robotic creatures across the city as any of the three selectable characters (each with their own attacks and strengths/weakness). This means you must clear a stage by reaching its finish line before your "Anergy"(sic) runs out, and then battling the corresponding boss creature/machine in an individual stage.
As mentioned, your bike can change into several modes, each with its pros and cons (robot mode is slow but combat-oriented, bike mode is fast but weak, and buggy mode is slower but easier to maneuver). You'll need to use them all however, as each stage is filled with enemies and traps. Combat is handled mainly in robot mode and depending on the amount of enemies you hit simultaneously, a combo meter fills up that can be used to unleash super moves (useful for clearing enemies and mines). Features a single player "Operation" campaign, as well as a comprehensive Training mode.