Successfully complete the indicated task to unlock the corresponding cheat option at the "Unlockables" menu:

1. Infinite Ammo: Get 52 medals/badges in Story mode.
2. Infinite Grenades: Get 56 medals/badges in Story mode.

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

1. I'm Supposed To Die Tonight (20 points): Complete Mission 1 on any difficulty.
2. Get In My Car (20 points): Complete Mission 2 on any difficulty.
3. Candy Shop (20 points): Complete Mission 3 on any difficulty.
4. Straight To The Bank (20 points): Complete Mission 4 on any difficulty.
5. Disco Inferno (20 points): Complete Mission 5 on any difficulty.
6. Amusement Park (20 points): Complete Mission 6 on any difficulty.
7. Gunz Come Out (20 points): Complete Mission 7 on any difficulty.
8. I'll Still Kill (20 points): Complete Mission 8 on any difficulty.
9. Gotta Make It To Heaven (20 points): Complete Mission 9 on any difficulty.
10. Got Paid (25 points): Complete all missions on Easy or better difficulty level.
11. Gangsta (50 points): Complete all missions on Normal or better difficulty level.
12. Bulletproof (100 points): Complete all missions on Hard difficulty level.
13. Packin' Heat (10 points): Unlock all pistols.
14. Point Blank (10 points): Unlock all close combat weapons.
15. Rifled (10 points): Unlock all assault weapons.
16. Explosive (10 points): Unlock all special weapons.
17. Tooled Up (50 points): Unlock all weapons.
18. Wanna-be (10 points): Obtain 15 or more Silver Badges.
19. Regular (25 points): Obtain all Silver Badges.
20. Hardcore (50 points): Obtain 15 or more Gold Badges.
21. O.G. (100 points): Obtain all Gold Badges.
22. Savior (5 points): Revive a coop player.
23. We're Supposed To Die Tonight (10 points): Complete Mission 1 on any difficulty as a member of G-Unit.
24. Get In Our Car (10 points): Complete Mission 2 on any difficulty as a member of G-Unit.
25. Our Candy Shop (10 points): Complete Mission 3 on any difficulty as a member of G-Unit.
26. We're Going Straight To The Bank (10 points): Complete Mission 4 on any difficulty as a member of G-Unit.
27. Our Disco Inferno (10 points): Complete Mission 5 on any difficulty as a member of G-Unit.
28. Our Amusement Park (10 points): Complete Mission 6 on any difficulty as a member of G-Unit.
29. Our Gunz Come Out (10 points): Complete Mission 7 on any difficulty as a member of G-Unit.
30. We'll Still Kill (10 points): Complete Mission 8 on any difficulty as a member of G-Unit.
31. We Gotta Make It To Heaven (10 points): Complete Mission 9 on any difficulty as a member of G-Unit.
32. G-Unit (50 points): Complete all missions on any difficulty as a member of G-Unit.
33. Hit and Run (10 points): Run over a foot soldier in a driving section.
34. Ramping Up (10 points): Complete any of the ramp scenarios in a driving section.
35. Death From Above (10 points): Destroy 50 vehicles and destroyable objects on the flying level without dying.
36. Up Close (5 points): Perform a counter kill.
37. Got It Done (5 points): Successfully complete one scenario.
38. Scenario Master (20 points): Successfully complete 50 scenarios.
39. Black Belt (40 points): Unlock all counter kill packs.
40. Sharpshooter (25 points): Kill an enemy by shooting a rocket or grenade out of the air using Gangsta Fire.
41. Fly Poster (15 points): Collect all 5 posters on any level. This can also be achieved by assisting another player in Coop.
42. Target Practice (15 points): Shoot all 5 targets on any level. This can also be achieved by assisting another player in Coop.
43. Flying High (10 points): Score air time from a single character for more than 10 seconds.
44. Massacre (10 points): Kill 5 enemies fast enough to score a 5 kill combo.
45. Millionaire (50 points): Have 1,000,000 dollars in the bank.

Additionally, there is one secret achievement:

Not Bulletproof (0 points): Died on Easy difficulty