Accomplish the indicated achievement to get Gamerscore points:

First Boss: Defeat the final Boss in level 1 on the default settings.
Second Boss: Defeat the final Boss in level 2 on the default settings.
Third Mini Boss: Defeat the mini Boss in level 3 on the default settings.
Final Boss: Defeat the final boss in level 3 on the default settings.
High score: Get first place on the game score board on the default settings,
Level 1 Master: Successfully complete level 1 without continuing on the default settings.
Level 2 Master: Successfully complete level 2 without continuing on the default settings.
Level 3 Master: Successfully complete level 3 without continuing on the default settings.
Cash Pile: Get 2,000,000 points at the end of level 1.
Co-Op: Successfully complete level 1 with another player on the default settings.
Co-Op Master: Successfully complete the game with another player on the default settings.
Game Master: Successfully complete the game without continuing on the default settings.