This post contains spoilers for God of War I, II, and III.
Defending God of War's artistic merit is tricky. The story is rife with plot holes, continuity problems, and cheesy dialogue. Much of the violence and character interactions can be viewed as juvenile and gratuitous, if not obscene and misogynistic. As a character, Kratos appears to operate on a narrow emotional spectrum that spans from "angry" to "super angry."
Despite all this, Kratos is actually an extremely well-realized character and his story is an example of outstanding single-player narrative design. The themes (regardless of their maturity or complexity) explored in God of War's story and those conveyed through its gameplay complement each other. When playing a God of War game, the player is both digesting and actively constructing the game's narrative through their actions.
Violence is the strongest motif in God of War, and it pervades every situation in which Kratos and the player find themselves. By selling his soul in exchange for becoming an unstoppable warrior, Kratos ushers himself into a world in which things exist only to be destroyed. His hubris leads him to tragically kill his family, which causes him to channel his despair into punishing others rather than changing himself. His world becomes one of brutal utilitarianism: Anything that cannot be used as a weapon or a tool against his enemies is destroyed, and anyone whose death would advance his goal is a target.
The games' rules mirror this singular focus. With few exceptions, if something is on the screen, it is meant either to be destroyed or to be used to destroy something else. Devoid of any stealth, cover, or dialogue mechanics, the games makes every enemy that appears a target to attack. Any humans unfortunate enough to cross the player's path are killed and exploited for extra health, experience, or as gruesome objects that aid in solving environmental puzzles. Collateral damage is, at worst, neutral: at the very least, crushing optional enemies and pieces of the environment does nothing. Usually, it rewards the player's thorough and inventive destructive tendencies through narrative progression and ability enhancement. It is in the player's best interest to adopt Kratos' willingness to devastate the world and its inhabitants. Such behavior both matches and enhances the player's understanding of the Kratos they see in the cutscenes.
Like Kratos, the player interprets the world through combat. The game's dominant mode of expression is using the controller buttons in various combinations to kill beasts and people. Even when the action cools, the player still uses combat skills to interact with world: a door that must be forced open requires the player to mash the circle button in the same way they would when they are trying to ram a knife down a Minotaur's mouth. If a path is obscured by debris, the same deadly attacks used against enemies are used to destroy inanimate objects. Operating a simple switch or opening a treasure chest is done with the same forceful movements and angry vocalizations that happen during battle, which suggests that Kratos and the player are at war everything around them.
The tendency to interpret the world through violence is uncomfortably apparent during the infamous sex mini-games. As the camera pans a away from Kratos and his mate (or mates), button prompts identical to those used when killing enemies begin to appear. The player uses the same gameplay techniques during sex that are used to tearing peoples' heads off, and Kratos' grunts of exertion are largely indistinguishable from those made while slaughtering foes. When the encounter ends, the player is rewarded with experience points that are used to make Kratos even more deadly. Not only are women treated in the same way as the beasts Kratos and the player kill, they yield an identical reward when conquered. Like everything else in the game, their interaction with Kratos and the player is expressed through the language of violence and combat.
The quicktime events found throughout the game represent Kratos' reactionary, brutal nature and train the player to adopt his mindset. God of War is the story of a perpetual soldier who constantly performs deadly actions in order to survive and accomplish his goals. Kratos' predisposition to kill first and ask questions later caused the death of his loved ones and allies, but it is also what keeps him alive and striving towards his revenge. By the end of the game, the player has been trained to identify split-second opportunities for violence and to capitalize on them without having to think. Kratos inhabits a binary world governed by the law "kill or be killed." This rule is conveyed through games' rules: on a large scale, success is defined by killing enemies before they can kill the player. Peppered within the experience are quicktime events that distill the binary nature of success to its most basic form. Success is always measured in absolute terms.
In God of War III, the player and Kratos are tasked with ending the seemingly infinite cycle of destruction that takes place within the gameplay and the plot. Ultimately, Kratos accepts that his battle will only end when he abandons his need to fight. During the last fight against Zeus, the player is forced to come to a similar realization. As the player assumes a first person perspective, they are prompted to mash the circle button to mercilessly pummel Zeus to death. Each successful punch causes blood to spring from his face, and Kratos' (along with the player's) sight is soon completely obscured by a red wall of gore.
The player is free to keep pounding away and can still hear every successful punch land on the Zeus' lifeless corpse. The player can continue punishing their nemesis long after he utters his last pathetic groan, but it soon becomes apparent that if they continue fighting, the game will never end. Both Kratos and the player must accept that their bloodlust leads to an endless chain of violence. Such a chain has been demonstrated throughout the series by the many violent plot points and by the hundreds of massacres committed by the player. Ultimately, the only way to end Kratos' story is by forsaking the mindset that originally created it.
Of course, even Kratos' attempts at peace are violent. In God of War I, the player watches as he attempts to end his suffering by committing suicide. Instead of dying, he is saved and then tempted with the promise of more power and the opportunity to exact revenge. God of War II illustrates the escalating consequences of this temptation, and both Kratos and player are continually teased with the prospect of success. In God of War III, things come full circle and Kratos finally succeeds in ending his own life. However, he needs the player's help to do so. In order to finish the game, the player must not only abandon violence towards their enemy, they must actively turn it towards themselves. Using a button command previously reserved for vanquishing enemies, the player ends the game by causing the event they have spent the entire series trying to prevent: the death of Kratos, their avatar.
While the content and execution of God of War's themes may be morally questionable, the plot and gameplay are uniquely congruent. In a story about killing gods, nothing is sacred, and so it is consistent that the player is prompted to callously exploit and destroy everything they encounter. Chaining together vicious combos and learning to win quicktime events is how the player interacts with everything and everyone in the game. The game defines everything in terms of combat, which serves to reflect Kratos' character: he is a single-minded, reactionary figure whose efforts to rectify violence with more violence only serves to victimize those around him. In the end, Kratos and the player must turn this violence against themselves to end the story.
The moment the sword pierces Kratos the story as told by the plot and the story as told by the player's actions converge. Kratos may not be an overly-complex, noble, or even likable character, but he is understandable because the game requires the player to personify him through action. The player is both constrained and rewarded by the same violence that defines the character, which adds a depth of knowledge unique to performance art. To successfully play God of War is more than simply understanding or believing Kratos as a character; to succeed with Kratos is to be Kratos.