Reach the indicated level to unlock the corresponding bonus.

Level 5: Throwing Knife
Level 6: SCAR-L (Assault Rifle)
Level 8: SPAS-12 (Shotgun)
Level 10: P99 (Handgun)
Level 11: Blind Eye
Level 12: Dragunov (Sniper)
Level 13: Scrambler (Tactical)
Level 14: PKP Pecheneg (LMG)
Level 15: Hardline
Level 15: Revenge (Death Streak)
Level 16: MP9 (Machine Pistol)
Level 18: CM901 (Assault Rifle)
Level 19: Sitrep
Level 20: Specialist (Strike Package)
Level 21: EMP Grenade (Tactical)
Level 22: A550 (Sniper)
Level 22: Extreme Conditioning
Level 24: Javelin (Launcher)
Level 26: AA-12 (Shotgun)
Level 27: Assassin
Level 28: PP90M1 (SMG)
Level 29: Smoke Grenade (Tactical)
Level 30: MP412 (Handgun)
Level 30: Steady Aim
Level 32: Type 99 (Assault Rifle)
Level 32: Final Stand (Death Streak)
Level 36: Skorpion (M. Pistol)
Level 37: Bouncing Betty (Anti Personnel Mine)
Level 38: P90 (SMG)
Level 39: SCAVENGER
Level 40: Stinger (Launcher; vehicle lock-on only)
Level 42: G36C (Assault Rifle)
Level 44: RSASS (Sniper)
Level 45: Trophy System (deflects enemy explosives/missiles)
Level 46: .44 Magnum (Handgun)
Level 47: Overkill
Level 48: Striker (Shotgun)
Level 50: ACR (Assault Rifle)
Level 51: Martyrdom (Death Streak)
Level 52: XM25 (Launcher)
Level 53: Claymore (Anti Personnel Mine)
Level 54: MK46 (LMG)
Level 55: Dead Silence
Level 56: PM9 (SMG)
Level 57: Dead Man's Hand (Death Streak)
Level 58: Five Seven (Handgun)
Level 60: MK14 (Assault Rifle)
Level 61: Tactical Insertion (marker to place your next re-spawn)
Level 62: Model 1887 (Shotgun)
Level 64: M320 GLM (Launcher)
Level 66: MSR (Sniper)
Level 68: AK-47 (Assault Rifle)
Level 69: C4 Explosives
Level 70: G18 (Machine Pistol)
Level 71: Hollow Points (Death Streak)
Level 72: M60E4 (LMG)
Level 74: MP7 (SMG)
Level 76: Desert Eagle (Handgun)
Level 77: Portable Radar (shows enemy moment within its radius)
Level 78: FAD (Assault Rifle)
Level 80: RPG-7 (Launcher)