Here is the full list of all 12 Feeding Frenzy 2: Shipwreck Showdown achievements worth 200 gamerscore.
Awarded for defeating the Intruder and completing the single player story mode
Awarded for eating 5000 fish
Awarded for unlocking all Fish Upgrades in the single player story mode
Awarded for accumulating 3 simultaneous fish shields
Awarded for completing a 'Barracuda Bonus'
Awarded for your first fish upgrade in the single player story mode
Awarded for reaching the maximum FRENZY multiplier in a single player game
Come first in a Frenzyfest Tournament
Complete Time Attack!
Compete in Party Games to accumulate 1000 Party Points
Eat 500 entire schools of fish, or swarms of bugs
Complete a Quadruple Flip