Full list of all 12 Gunstar Heroes achievements worth 200 gamerscore. It takes around 1-2 hours to unlock all of the achievements on Xbox 360.
You defeated Crab Force.
You began the game with each weapon.
You completed the game.
You defeated Golden Silver.
You defeated Green.
You defeated Black Fly.
You defeated Smash Daisaku.
You defeated Black Beat Stepper.
You defeated Orange.
You defeated Pinky Roader.
You defeated Bravoo Man.
You defeated Papaya Dance.