The player controls Leon S. Kennedy from a third-person, over-the-shoulder perspective in a mission to rescue the daughter of the President of the United States, Ashley Graham. The gameplay focuses on action and shootouts involving crowds of enemies in large open areas. The camera is focused behind Leon, and it zooms in for an over-the-shoulder view when aiming a weapon. Unlike previous games in the series, there is the addition of a laser sight that adds a new depth to the aiming, allowing the player to aim in various directions and easily change their placement at any time. Bullets affect the enemies specifically where they are shot: shots to the feet can cause enemies to stumble, while shots to the arms can cause them to drop their weapons.
An image of a young man defending himself against a hoard of humanoid enemies in a village setting. The camera is behind the man's shoulder, placing him in the bottom left corner and the attackers in the background of the picture.
Leon in battle with a group of Ganados. Unlike previous entries in the series, Resident Evil 4 places the camera constantly behind and over the protagonist's shoulder. The laser sight enables the player to target key hit zones on enemies.
Another new aspect of Resident Evil 4 is the inclusion of context-sensitive controls. Based on the situation, the player can interact with aspects of their environment: kicking down a ladder, jumping out of a window, or dodging an enemy attack. There are also dynamic cut scenes, in which the player must press buttons indicated on-screen to execute actions such as dodging a falling boulder or wrestling an enemy to stay alive. These are often incorporated into the game's many boss battles, where the player must avoid instant kill attacks.
The main enemies are violent villagers referred to as Los Ganados ("The Cattle" in Spanish). Los Ganados can dodge, wield melee and projectile weapons, and are capable of working collectively and communicating with each other. They were once simple farmers until becoming the product of an infestation of Las Plagas ("The Plague" in Spanish).
The inventory system of the game features a grid system, represented by an attache case, that has each item take up a certain number of spaces. The case can be upgraded several times, allowing for more space. Weapons, ammunition and healing items are kept in the case, while key items are kept in a separate menu. Items may be bought from and sold to a wandering merchant that appears in various locations throughout the game. He sells first aid sprays, weapons, allows for weapons to be upgraded and buys various treasures that Leon finds. The various weapons each have their own advantages and disadvantages.
Capcom added new content made specifically for the PlayStation 2, which was later incorporated into the PC and Wii releases. The largest addition is "Separate Ways", a minigame which revolves around Ada Wong's involvement in Resident Evil 4 and her connection to Albert Wesker, a former member of STARS, who is now attempting to revive Umbrella. "Ada's Report", a five-part documentary, analyzes Ada's relationship with Wesker and his role in the plot. Other unlockable content in all versions included the minigame "The Mercenaries", "Assignment Ada", a small minigame using Ada to retrieve plaga samples, new costumes for Leon and Ashley, new unlockable weapons and a Movie Browser.
Racoon City has been destroyed under orders from the U.S. government, after the company Umbrella set an experiment that caused major incidents. Leon S. Kennedy is recruited by the U.S. Secret Service after they learned of his involvement within Raccoon City. Leon is sent on a mission to rescue Ashley Graham, the President's daughter, who has been kidnapped by a mysterious cult. He travels to a rural village in Europe, where he encounters a group of violent villagers who pledge their lives to Los Illuminados ("The Enlightened Ones" in Spanish), the cult that kidnapped Ashley.
While in the village, Leon is captured by its chief, Bitores Mendez, and injected with a mind-controlling parasite known as Las Plagas. He finds himself held captive and tied up back to back with Luis Sera, a former Los Illuminados researcher. The two work together to escape, but then quickly go separate ways. Leon discovers that Ashley is being held in a chapel, and rescues her. They both escape from the chapel after Osmund Saddler, leader of the Illuminados, reveals his plans to use the Plagas they injected on Ashley to cause a disaster in the United States once she is back. Leon and Ashley try take refuge inside the castle of Ramon Salazar, a servant from Saddler, but are attacked by more Illuminados. Both of them are separated by Salazar's traps. Meanwhile Sera searches for the pills to slow Leon's and Ashley's infection, and then to bring a plaga sample. He brings the two items to Leon but is killed by Saddler, who takes the sample, while the pills to suppress the infection remain in Leon's hands. While in the castle, Leon briefly encounters Ada Wong, a woman from his past that supports him across his mission. He then battles his way through the castle until killing Salazar. Leon learns that Ashley has been taken to a nearby island research facility, and goes to find her.
Leon later learns that one of his former comrades from his years of training, Jack Krauser, is alive and is responsible for Ashley's kidnapping. Both Ada and Krauser are actually working together for a third party related with Umbrella, and that Krauser intends to kill Saddler when he gets the chance. Saddler knows this, and he orders Krauser to kill Leon, knowing that no matter which one dies, he will benefit. After Krauser's defeat, Leon rescues Ashley, and they remove the Plagas from their bodies using a specialized radiotherapeutic device. Leon confronts Saddler after seeing Ada as his hostage. With Ada's help, Leon kills Saddler, and Ada takes the sample. She then escapes from the complex in a helicopter, leaving Leon and Ashley to escape via her jet-ski as the island explodes.
* OS: Windows® 2000/XP (only)
* CPU:1 GHz Pentium® III or AMD Athlon
* RAM: 256 MB
* HDD: 7000 MB free disk space
* Graphics: 128 MB DirectX® 9.0c-compliant AGP or PCI Express graphics card (256 or higher for High Graphics Detail support)
* Sound Card: DirectX 9 Compatible
* DirectX: Version 9.0c