Resident Evil 4 Unlockables and Glitches (GameCube)

Resident Evil 4's game mechanics have been completely revamped to incorporate fast-paced gunplay, quick controls and shootouts involving massive crowds of enemies in large open areas. This, combined with an abundance of healing items and ammunition, results in a different gameplay experience from other Resident Evil games. Previous titles in the series have focused on exploration and conservation of ammunition - in RE4, the player can fire more ammunition and kill more enemies in one playthrough than in all of the other Resident Evil games combined (not including the Gun Survivor sub-franchise, in which the player is deliberately given infinite pistol ammunition). A typical play-through can result in the player killing upwards of 900 enemies.

Because the game contains no zombies, this installment is a radical departure from the series formula. Instead, the main enemies are parasitically-controlled humans referred to as "Los Ganados". Significantly smarter and quicker than the zombies from previous games, Ganados are a very different sort of foe. These new enemies dodge, wield melee and projectile weapons, and are capable of working collectively. Once simple farmers, these Ganados are the product of an infestation of Las Plagas, parasites.

Unlockables

"Assignment Ada" Mini-Game
Complete the main game once

"The Mercenaries" Mini-Game and Characters
Ada Wong for use in The Mercenaries - Get a four-star rating in the Pueblo map of The Mercenaries

Albert Wesker for use in The Mercenaries - Get a four-star rating in the Waterworld map of The Mercenaries

Hunk for use in The Mercenaries - Get a four-star rating in the Island Commando Base map of The Mercenaries

Jack Krauser for use in The Mercenaries - Get a four-star rating in the Castle map of The Mercenaries

The Mercenaries Mini-Game - Complete the main game once

Alternate title screen
Alternate Title Screen - Complete the game once.

Bottle Caps
After you enter the Castle, and go through the Hall of Water(Y' Know.... that place that you have to protect Ashley as she turns the Cranks) to the Observation Hall. Next to the Merchant, a blue door with golden gun engravements lies in wait. Go through the door and begin the Target Practice game. Select Game Type A to begin a game. During certain portions of the game, other blue doors similar to this can be found. Enter them and finish the Target practices by earning 3000 points or higher to get 6 bottle caps. After you get 6, talk to the merchant and end the game. If you collected 6 different caps of the same game type, you will get some pesetas.

Ada Wong - Score 4000 or more on Game Type A. Alternately, hit all of the targets on Game Type A

Ashley Graham - Score 3000 or more on Game Type A

Bella Sisters - Score 4000 or more on Game Type B. Alternately, hit all of the targets on Game Type B

Don Diego - Score 3000 or more on Game Type B

Don Esteban - Score 3000 or more on Game Type B

Don Jose - Score 3000 or more on Game Type B

Don Manuel - Score 3000 or more on Game Type B

Don Pedro - Score 4000 or more on Game Type C. Alternately, hit all of the targets on Game Type C

Dr. Salvador - Score 3000 or more on Game Type B

Isabel - 3000 or more points in Game D.

J.J. - 4000 or more points in Game D. Hit all targest in Game D except Ashley.

Leader Zealot - Score 3000 or more on Game Type C

Leon with Handgun - Score 3000 or more on Game Type A

Leon with Rocket Launcher - Score 3000 or more on Game Type A

Leon with Shotgun - Score 3000 or more on Game Type A

Luis Sera - Score 3000 or more on Game Type A

Maria - 3000 or more points in Game D.

Merchant - Score 3000 or more on Game Type C

Soldier w/ dynamite - 3000 or more points in Game D.

Soldier w/ hammer - 3000 or more points in Game D.

Soldier w/ stun-rod - 3000 or more points in Game D.

Zealot with Bowgun - Score 3000 or more on Game Type C

Zealot with Scythe - Score 3000 or more on Game Type C

Zealot with Shield - Score 3000 or more on Game Type C

Glitches

100% hit rate with Infinite Rocket Launcher.
To do this, you need at least one normal weapon, and the Infinite Rocket Launcer.

At the beginning of each chapter hit an enemy with any weapon once (any weapon other than the IRL) You can then fire away at anything with the Rocket Launcher, no matter if you hit or miss an enemy and you will get 100% hit rate at the end of the chapter. This happens because the game does not register the Rocket Launcher hits like the other weapons hits.

How to make the Gatling Gun appear without allowing the red monk to use it
In the castle, there is a glitch where you can make the Gatling Gun appear without allowing the red monk to operate it.
First, progress normally and let the red monk escape. Once you return to the turret room, he will be operating the gatling gun. Immediate leave the room and return to the main hall with the merchant and save.

Load the game and re-enter the turret room. You need to chase the red monk again until he returns to the turret room. When you return to the turret room, the turret will be raised, but the red monk will be standing outside of the turret ring! Without the turret on his side, finish him with ease!

Instant KO against gatling gun Ganados
When you get to the second wave of enemies when Mike is helping you, destroy the guns with the Infinite Rocket Launcher BEFORE you enter that area. Once you go past the shutters, the Ganados will rush to their posts, but only to die immediately. It will also work with the regular Rocket Launcher, but that only has one shot, so... yeah.

Quickly reload your weapon
Whenever you have the chance to dodge (A and B, or L and R), if you are in the middle of a reload (Or just started one), and you perform the dodge, after you dodge your weapon you will have a full clip of ammo, as if you fully reloaded it. Useful for fighting bosses where you don't have a lot of time, or when you must reload an item that would normally take a while (Such as the Broken Butterfly).

Haven't decided what version of the game to play? Here's a video comparison between the GameCube version and the PC version: