RESIDENT EVIL 4 CHEATS

Professional Mode:
If you want to make a new game after you kill that damn Saddler, you'll be given the option of choosing Professional Mode, which is a more difficult game option, (trust me!). Enemies will take a fair amount of more damage, so you'll have to go easy on the ammo.

New Round:
If you bothered saving the game after beating Saddler, then you load it from the load menu, you'll be able to start a new game, but will keep all of the weapons and items you had on you at the end of the last one.

New Weapons:
On play-throughs of the game, you'll be able to buy both the Matilda and the Infinite Launcher from the merchant. The Matilda is an automatic pistol, while the Infinite Launcher is a well... a rocket launcher; it'll sting your wallet a cool million pesetas to buy it, but it's worth it. The Chicago Typewriter and the Handcannon can both be unlocked by playing through the two mini-games that are unlocked at the end of completion of this wonderful game.
(supplied by: bloodygud)