Enter the following codes at the Cheats Screen to unlock the corresponding effect

Get Invincibility:
Invincibility

Half Health:
Iron Man

No Civilian Traffic:
Open Road

Always Full Justice:
Law Lord

Double Negative Justice Loss:
Reoffender

Can't get Thrown out of Vehicles:
Sticky Feet

Make Water Choppy:
Wild Water

Double Wheel Size:
Big Wheels

Get Double Damage:
Double Damage

Move Faster:
Speed

Police Shoot Blue Lasers:
Laser Law


Unlock Vehicles for Time Trial.
Complete the following levels in the Capelli missions to unlock the corresponding vehicles.

Unlock JME Marlin:
Get an A on Cold Contract

Unlock KMT Seareaver:
Get an A on Cold Contract

Unlock Hampton Monte Christo:
Get an A on Rat Race

Unlock Hampton Avenger:
Get an A on Rat Race

Unlock JME Otter IV:
Get an A on Witness Protection

Unlock Zephyr ATS Law Enforcer:
Get an A rank on Don the run


Unlock Deflective Armour:
Beat 'The Big Game' mission under the Killer 66 Gang to unlock 'Major' rank to be able to unlock Deflective Armour