Activating this trainer:
If not state otherwise below, press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.

Promo Options:
Score: Score

Trainer Options:
NumPad1: Unlimited Health
NumPad2: Unlimited Ammo
NumPad3: Freeze Timer

Editor Options:
Currency: Money
Score: Score
Heat: Total Police Heat Accumulated

Notes:

Unlimited Health:
Toggle on to try and keep health full.  May not protect from severe, instant, large damage.

Unlimited Ammo:
Toggle on and most weapons that you shoot, when you fire you have plenty of ammo.

Freeze Timer:
Toggle on and some of the timers in the game will not count down.