The story: The evil Bydo aliens threaten to take over Earth. Only some guy in a fighter called the R-9 can destroy the Bydo and save the planet.
The gameplay: The game introduces a unique item called a force pod. It can be attatched to the front or back of the ship and can fire secondary weapons and absorb bullets. It can be detached from the ship allowing it to hit hard-to-reach places with its own bullets. This game series is very difficult and requires intense memorization skills.