GRAND THEFT AUTO III UNLOCKABLES
Tank
Complete all the storyline missions and the tank will appear at Phil's place.
Health
Save 35 pedestrians in the ambulance mode and a health refill will appear outside any of your save points.
Adrenaline
Save 70 pedestrians in the ambulance mode and an adrenaline pill will appear outside any of your save points.
Infinite Run
Complete the Ambulance level 12 and Infinite Run will be granted.
Wear prisoner outfit
You need a saved game for this. Start a new game, and after the beginning cutscene load your other game. You'll have everything, but you'll still be wearing a prisoner outfit.
Fire Truck Bonus Weapon
While not doing a normal mission, get in a Fire Truck and press R3. There is a Fire Station on each island. Put out 20 fires on each island and a Flame-thrower will always appear at one of your three save points.