Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Going Solo (20 points): Complete the Single Player Campaign.
Likes the Drink (15 points): Kill 170 enemy worms by knocking them into the water.
Ranked Master (30 points): Achieve 17 wins in each of the following Ranked Match types: Standard, Pro, Crazy Crates and Fort.
Armageddon an Award (5 points): Deploy the Armageddon weapon 10 times.
Get Your Lob On (20 points): Win a game using just the Grenade.
Fast, Pink & Hard (30 points): Win a Pro Ranked Match in under 3 minutes.
Six Pest (10 points): Kill 6 enemy worms in a single turn.
Cheeky Flocker (10 points): Deploy 25 Sheep in any Ranked Match.
Prod for Victory (10 points): Win a game by using the Prod.
Oldest Swinger in Town (20 points): Use the Ninja Rope 1000 times.
Hallelujah! (10 points): Deploy the fabled Holy Hand Grenade.
FireStarter (20 points): Use fire weapons 200 times.