NOTE: As their name suggests hints are not exactly Resident Evil 4 cheats, and are usually just simple (but very useful) tips on how you can unlock secret level, features, find hidden areas and such. Hopefully these will make playing Resident Evil 4 even more entertaining.
More Money for Beerstein and Elegant Mask
When you find these items do not sell them right away. You can increase the value of the items with gems.
Snake in the Box
Sometimes when you destroy the wooden crates a snake will jump out and bite you. If you keep slashing with your knife when the box breaks you can kill the snake and receive a healing egg.
Quick Aiming
There is a quick way to center your gun when aiming up or down. Simply tap the L1 button (takes out your knife) and you will quickly aim straight ahead.
Raise Max Health
If you mix: GREEN HERB + RED HERB + YELLOW HERB. It restores your health completely and raises your max health.
Reload Your Upgraded Gun
Whenever you upgrade your gun's capacity it fills the weapon with ammo. So don't reload before you buy the upgrade. This works great with weapons that have very little ammo (such as the magnum revolver 'Broken Butterfly'); after you use up the gun's magazine, simply look for the merchant and upgrade the ammo capacity.
The First Shotgun
There are three main buildings in the village where you first see the chainsaw not-zombie. The shotgun is in the northeast building, on the second floor of the house.
Unock Mercenaries
Beat the game to unlock the mercenaries mini game.
Unlock Assignment Ada
Beat the game to unlock the mini game: Assignment Ada.
Unlock Broken Butterfly
In the hall south of the hedge maze there is a locked door. Return to that area with Ashley, piggy back with her and she will unlock the door. This reveals the broken butterfly.
Unlock Punisher pistol
You, know the guy, who runs around and sells you upgrades for weapons, he has a secret quest for you. You must search two areas of the game for blue medallions and shoot them. Finding and shooting more than 10 of the medallions will reward you with the punisher pistol. This weapon has slightly upgraded statistics and penetrating bullets.
Unlock Mercenaries Characters
To unlock Ada Wong in Mercenaries get a 4 star rating on the Pueblo map of the game.
To unlock Albert Wesker in Mercenaries get a 4 star rating on the Waterworld map of the game.
To unlock Hunk in Mercenaries get a 4 star rating on the Island Commando map of the game.
To unlock Jack Krauser in Mercenaries get a 4 star rating on the Castle map of the game.
Exclusive Weapon Powers
Each weapon has a special "exclusive power" when all of its stats are custom tuned to the maximum:
Handgun - Increases the chance of a headshot being fatal by a factor of five (5% or 20%, take your pick)
Punisher - Each bullet can penetrate up to five bodies
Red 9 - Increases firepower to 5.0
Blacktail - Increases firepower to 3.4
Matilda - Increases magazine capacity to 100
Shotgun - Increases the effective damage range of the gun
Riotgun - Increases firepower to 10.0
Striker - Increases magazine capacity to 100
Rifle - Increases firepower to 18.0
Semiauto Rifle - Decreases firing speed to 0.40 seconds
Broken Butterfly - Increases damage to 50.0
Killer7 - No exclusive power!
TMP - Increases firepower to 1.8
Minethrower - Adds homing ability to mines and increases their blast radii.
Double Broken Butterfly Ammo
If you buy the broken butterfly before you find it, you can hold twice the ammo. The shopkeeper will not sell you this gun if you already have it.
Funny Character Animations
When Ashley is standing on a ledge and you are below her, look up at her and she will hold down her skirt and say something about you being a pervert and one or two other funny lines.
Los Gigante
In Chapter 1-1, along the path towards the village you will run along a white dog trapped in a bear trap. If you help this dog he comes in handy later when you are fighting Los Gigante for the first time. About midway through the fight, you will hear the dog bark and he will come to your aid. Los Gigante becomes distracted, and begins to attack the dog rather than you.
Fishing
If you are low on health spray and herbs when at the lake take aim at the fish and fire away. When you hit a fish it floats. Jump in the boat and ride over the fish and take it. Depending on the size of the fish it will give you health.
Keep Money
When you beat the game you are able to keep all of your remaining weapons and items. Start a new game with the "cleared game" feature.
Lake Shooting
When you are at the lake before you face Del Lago (the thing in the water) stand on the dock right before the water and start firing into the water. The creature will not appreciate this.
Quick Side Turn
While holding R, tilt the C-Stick left or right, then quickly release and pull the R trigger again. You will turn almost instantly towards that direction.
Get Two Attacks on Saddler
When fighting Saddler, knock him down and stand near his eyeball head so that the "Knife" action appears. Shoot him instead and then start tapping "A" to do the action attack as well.
Big Money
In the Castle after you get out of the sewer you will appear at the top of a large ball room wear there are some monks doing a sacrifice. If you alert them they all run away but if you throw a grenade down every single person you kill will drop a spinel or a los illuminados pendent.
Easter Egg: King Leon
In chapter 5-3, right before the room with the lasers, there's a red throne room. Approach the throne and hit 'A' to have Leon sit upon the throne in all his glory.
Easter Egg: Capcom Game Promo
Late in the game, Leon will stumble across a weapon aptly called the Killer 7, an obvious tip of the hat to Capcom's Killer 7 videogame.
Easter Egg: S.T.A.R.S. Warning
Similar to the FBI Warning on commercial movies, a S.T.A.R.S. and Racoon City Police Department warning is in the game. Check out the end of the credits.