Each weapon is unlocked by completing the mission and achieving the Silent Assassin rating.

Mission 1: CZ 2000 Dual Pistols
Mission 2: Micro Uzi Dual Submachine Guns
Mission 3: Silverballer Silenced Dual Pistols
Mission 4: Magnum 500 Dual Pistols
Mission 5: Sawed-Off Shotgun Dual
Mission 6: M4 Carbine Silenced Assault Rifle
Mission 7: SG220 .S Dual Pistols
Mission 8: MP5 Silenced Submachine Gun
Mission 9: AK 74 Silenced Assault Rifle
Mission 10: GK 17 Dual Pistols
Mission 11: Micro Uzi Silenced Dual Submachine Guns
Mission 12: PGM Silenced Sniper Rifle