Complete the following achievements to unlock Xbox Live Gamerscore points.

Achievements	How to unlock
Barren ( 20 points )	Destroy all mushrooms on the screen Centipede - Default difficulty.
Entity ( 20 points )	Have 3 lives in hand Millipede - Default difficulty.
Eradicate ( 20 points )	Reach wave 8 without a millipede reaching the bottom Millipede - Default difficulty.
Exterminate ( 20 points )	Reach wave 8 without a centipede reaching the bottom Centipede - Default difficulty.
Lunatic ( 20 points )	Score 25,000 points Millipede - Throttle Monkey mode.
Maniac ( 20 points )	Score over 15,000 Centipede - Throttle Monkey mode.
Marauder ( 10 points )	Score 125,000 points Millipede - Default difficulty.
Poison ( 20 points )	Destroy a spider for 1800 points Millipede - Default difficulty.
Prowler ( 10 points )	Score over 41,916 to get on the high score table Millipede - Default difficulty.
Slayer ( 10 points )	Score over 16,543 points to beat the high score table Centipede - Default difficulty.
Spirit ( 20 points )	Have 3 lives in hand Centipede - Default difficulty.
Stalker ( 10 points )	Score over 50,000 points Centipede - Default difficulty.