Resident Evil 4 cheats and cheat codes for Gamecube

Get PRL 412 laser weapon with infinite ammo:
Complete Leon's Story on Professional mode

Buy Thompson Gun in new game+:
Complete Leon's story mode on any mode and complete Ada's story 
mode (Separate Ways). Buy it from the Roma merchant.

Ada can also have own weapon. Complete Assignment Ada Mission, after
speak again with the Roma merchant to access it.

Unlockable Modes and Clothes
Finish the main game on any difficulty mode to unlock: 
Professional Difficulty level
Mercenaries Challenge 
Separate Ways Mini-Campaign 
Different clothes for Ashley, Leon and Ada Wong 

Unlockable Costumes for Leon and Ashley:
Complete the Separate Ways mode

Unlock Mercenaries mini-game: Bonus characters: 
Reach 4 star rating in the following areas

Ada Wong: Pueblo
Albert Wesker: Waterworld
Hunk: Island Commando
Jack Krauser: Castle 

Chicago Typewriter:
Finish the Assignment Ada mini-game
You will able to buy the Tommy gun with infinite ammo for 1 million pesetas. 

Unlock Handcannon:
Reach a 5 star rating with all mercenaries
Upgrade all of the Handcannon's options to get unlimited ammo.

Handcannon with unlimited ammo:
Finish the game two times. The Handcannon will be available as 
soon as you start the game again for 0 Pesetas.

Magnum ammo for the killer 7 is not abundant and can rarely be found. 
Save ammo for bosses.After hitting almost any boss with the rocket launcher,
 the boss will be deafeated.