Weapons
While playing, enter the following to stock certain sets of weapons:

Set 1 ... UP, SQUARE, SQUARE, DOWN, LEFT, SQUARE, SQUARE, RIGHT. (Unverified)
Set 2 ... UP, CIRCLE, CIRCLE, DOWN, LEFT, CIRCLE, CIRCLE, RIGHT. (Unverified)
Set 3 ... UP, X, X, DOWN, LEFT, X, X, RIGHT. (Unverified)

Miscellaneous
While playing, input the following codes:

Stock One-Quarter Million ... L1, R1, TRIANGLE, L1, R1, CIRCLE, L1, R1. (Unverified)
Stock armor ... L1, R1, CIRCLE, L1, R1, X, L1, R1. (Unverified)
Stock health ... L1, R1, X, L1, R1, SQUARE, L1, R1. (Unverified)

Submitted by TimeTaker13
Generate a pistol at all safe houses.
Collect 10 hidden packages.

Generate a shotgun at all safe houses.
Collect 20 hidden packages.

Generate a armour at all safe houses.
Collect 30 hidden packages.

Generate a python at all safe houses.
Collect 50 hidden packages.

Generate a laser scoped sniper rifle at all safe houses.
Collect 70 hidden packages.

Generate a rocketlauncher at all safe houses.
Collect 90 hidden packages.

Generate $50,000 at all safe houses.
Collect 100 hidden packages.

Generate a flamethrower at all safe houses.
Collect 80 hidden packages.

Generate a M4 at all safe houses.
Collect 60 hidden packages.

Generate a MP5 at all safe houses.
Collect 40 hidden packages.

Infinite Sprint
Complete the Ambulance Missions in Level 12.

Bickle '76
You must Drop off 100 Passengers in the taxi driver missions.

Hidden Packages
40 on Portland, 30 on Staunton, 30 on Shoreside. $250 awarded per package found.