Unlock the following by earning the appropriate number of Platinum Medals, earned by completing objectives in single player mode.

All Weapons: 17 Platinum Medals
Cloak: 13 Platinum Medals
Double Ammo: 7 Platinum Medals
Double Damage: 9 Platinum Medals
Full Ammo: 11 Platinum Medals
Full Battery: 15 Platinum Medals
Golden Gun: 1 Platinum Medal
Improved Battery: 5 Platinum Medals
Improved Traction: 3 Platinum Medals
Platinum Gun: 27 Platinum Medals
Slow Motion Driving: 25 Platinum Medals
Unlimited Ammo: 23 Platinum Medals
Unlimited Battery: 19 Platinum Medals