Single Player Cheats 
These only work for single player games (i.e., not Xbox Live). 
Press START and tap the D-Pad for the following codes.

Add 16,000 Credits 
UP, UP, DOWN, DOWN, LEFT, RIGHT 

Autoaim Toggle
DOWN, DOWN, DOWN, DOWN, UP, UP 

Big Heads 
UP, UP, LEFT, RIGHT, UP, DOWN 

IFF Glow 
RIGHT, RIGHT, RIGHT, UP, DOWN, LEFT 

Low Gravity 
UP, RIGHT, RIGHT, UP, UP, LEFT 

No Target Mode 
LEFT, RIGHT, RIGHT, LEFT, UP, DOWN 

Outfit Change 
LEFT, RIGHT, DOWN, UP, LEFT, RIGHT 

Player Clipping 
UP, DOWN, LEFT, RIGHT, DOWN, UP 

Miami: Movie billboard:
Across the street from the bank at a theater, there is a billboard that 
reads "Half Life: The Movie starts Friday at 11". 

Miami: Jump on top of movie billboard: 
Get three players on top of the S.W.A.T. truck. Go to the edge and pile up on top 
of each other. Then, have the top person try to jump onto the billboard. Note: This 
may require a fourth player.

Silent Weapons 
To silence a weapon, press B and flip to another weapon, then flip back and the 
first weapon will be silenced.