Grand Theft Auto IV is a third person action-adventure title taking place in an open world where players are free to do whatever they feel like doing. The game was developed by Rockstar North and published by Rockstar. It was released on April 29, 2008. Below you will find a complete list of cheats, codes, unlockables and PS3 trophies for Grand Theft Auto IV.

Cheats:

Press Up to display Niko’s cellphone. Press Up again to access the keypad. Type the codes. Please note: Once a code has been entered correctly, a new “Cheats” menu option will be available on your phone, below “Options“, where you can access the cheats without having to enter the phone number again. Do not save the game after enabling a code to avoid having problems with the game.

Restore Niko’s health, armor, and ammunition – Dial 4825550100 (aka GTA-555-0100)
Full health – Dial 3625550100 (aka DOC-555-0100)
Weapons tier 1 – Dial 4865550150 (aka GUN-555-0150). This will unlock the baseball bat, handgun, shotgun, MP5, M4, sniper rifle, RPG, and grenades.
Weapons tier 2 – Dial 4865550100 (aka GUN-555-0100). This will unlock the knife, Molotov cocktails, handgun, shotgun, Uzi, AK47, sniper rifle, and RPG.
Remove Niko’s wanted level – Dial 2675550100 (aka COP-555-0100).
Add one star to Niko’s wanted level – Dial 2675550150 (COP-555-0150).
Change weather and brightness – Dial 4685550100 (aka HOT-555-0100).
Spawn Annihilator police helicopter – Dial 3595550100 (aka FLY-555-0100)
Spawn Jetmax – Dial 9385550100 (aka WET-555-0100)
Spawn NRG-900 – Dial 6255550100 (aka MBK-555-0100)
Spawn Sanchez – Dial 6255550150 (aka MBK-555-0150)
Spawn FBI Buffalo – Dial 2275550100 (aka CAR-555-0100)
Spawn Comet – Dial 2275550175 (aka CAR-555-0175)
Spawn Turismo – Dial 2275550147 (aka CAR-555-0147)
Spawn Cognoscenti – Dial 2275550142 (aka CAR-555-0142)
Spawn SuperGT – Dial 2275550168 (aka CAR-555-0168)

Unlockables:

100% completion
Missions (68%): Complete all 90 main story and procedural missions.
Car Thefts (2%): Deliver all 30 vehicles to the garage.
Friends (10%): Unlock all unique abilities and complete all activities for all five friends (except Roman and Dwayne).
Activities (5%): Defeat the CPU or an in-game friend at all activities at least once.
Random Characters (5%): Find all 14 random characters and complete their encounter missions (except Jeff, Cherise, Clarence, and Ivan).
Most Wanted (2.5%): Kill all 30 pedestrians on the list.
Vigilante (2.5%): Complete all 20 vigilante crimes.
Flying Rats (2.5%): Find and kill all 200 pigeons.
Unique Stunt Jumps (2.5%): Complete all 50 jumps.

Remove ammunition limit
Get a 100% game completion.

Annihilator helicopter
Kill all 200 pigeons. The Annihilator is armed with rockets.

Rastah Color Huntley SUV
Complete 10 Package Delivery missions.