Level select:

At main menu enter these codes: 

Russian Base: Hold L2 + Up, press X
Black Isle:   Hold L1 + Up, press X
Tower Block:  Hold R1 + Up, press X 

Special Features option (beta ver.):
     Press  select to go into inventory screen and highlight the Small
Medkit. Hold L1 + L2 + R1 + R2 + Down + Circle and press Triangle.

All weapons, unlimited ammo & health packages (beta ver.):
     Press  select to go into inventory screen and highlight the Small
Medkit. Hold L1 + L2 + R1 + R2 + Up.

All items (beta ver.):
     Press  select to go into inventory screen and highlight the Large
Medkit. Hold L1 + L2 + R1 + R2 + Down.

Show FMV's (beta ver.):
     Go to the main menu and press R2 + Select.

Level select (beta ver.):
     First enter the main menu screen and highlight New Game. Then:

Hold L2 and press X - Black Isle
Hold L1 and press X - Russian Base
Hold R1 and press X - Tower Block