In the first level shoot the blue carto reveal a bazooka also on the third level 
shoot the dustbins to gather extra time.

To enter these codes, the game must be paused and you have to hold down 
R2 and then type them in. 

Die Hard
R=Right,L=Left,U=UP,D=DOWN,X=X, O=O,S=Square,T=Triangle
R U D S = GOD MODE
R S D O = 50 grenades
R S S D = Fat mode
D S T D = Bird...
R S T R = Forward is backward, Backward is forward
L O D S = Coordinates
10*T 4*R = Skeleton mode
D O O D T D = Silly mode
D S S R = 15 bullets
R U D D S R = Unlimited shotgun

Die Hard 2
R U D S = Map Editor (!)
D S T D = Skeleton mode
R S L O T D = Lots of ammo
O D D S X S = Fergus mode

Die Hard 3
L T R D = Fat mode
O D D T X S = Fergus Mode
R S L T X S D = Cars floats in air
D U L L D U L L D U L L = Everything is in a fat mode
L U L L S D = Slow motion
O D D S R = Very slow motion
O O S S D D X X = 999 turbos
O R D S T L = Sky cam mode
L O U D S R = Infinite lives

In Die Hard go to the left and when you see the blue car throw a grenade at 
it until its completly destroyed, thatshould reveal the AK 47!

On either dh1 or dh2, press select then hold r1, and press left right up 
down square. 

There is one code that works on all three games. 
In order to do this code, you must first pause the game. Hold R2 then press: 
Left, Right, up, down,square. Thecode has different effects on each three. 
For Die Hard 1, it gives you invincibility. It does something strange 
for Die Hard 2. In Die Hard 3, press start on controler 2, and it gives you a 
list of options.

While in the game, press select and go to map mode. Turn real time off by 
pressing L1. Then for full health, press:
TRI, X, X, CIR, X, TRI, SQU, SQU

For full ammo, press:
X, SQU, TRI, TRI, X, CIR, TRI, X