The game falls under the self-entitled sub-genre of "stop-and-pop" shooter which gives a summary of the central role that cover plays in the game. Using an over the shoulder perspective, made popular by Resident Evil 4, players hide, duck, slide, and bounce around the cover that's placed about every level. The "A" button is used exclusively to accomplish a variety of cover moves such as slamming behind a wall, moving from one cover position to another, and hopping over an obstacle.
Outside of the cover system GoW introduces many new enhancements and refinements to the world of shooting games. Following Halo's weapon system players can carry only two different main weapons at one time, one set of grenades, and pistol. Melee attacks are standard, with some weapons having special melee forms such as the machine gun's chainsaw, and "grenade tagging". One refinement on the aiming model that GoW brings is the use of an aiming arc for throwing grenades, so players can see precisely where the grenades will land even bouncing off of objects and obstacles.
Co-op plays a very large role in the game, allowing a second player either online, or through splitscreen, to take control of Marcus' partner Dom to play through the entire single-player campaign together. As a result, co-op play mechanics such as reviving your fallen teammate and having separate paths that compliment one another have a big focus.
Competitive multiplayer gametypes are also available, either 2-player splitscreen, or with a maximum of 8 people online. Players can choose to be part of the human COG side, or the Locust horde, with the differences being cosmetic and try to eliminate the other side. Unlike Halo 2's online functionality, Gears of War does not contain a party system, or a matchmaking system, finding games is done through the more traditional way of choosing an individual server.
Precursor: Humanity was living peacefully on the planet until one day the Locust that lived beneath the surface came out on "Emergence Day" and destroyed everything. Now the main war is lost but the humans are still struggling and fighting to take the planet back.
Gears of War follows Marcus and his marine unit as they try to destroy the horde's home base. The action is laid out across 5 different acts each split into subsections where the objectives are constantly changing. Narrative is forwarded from a combination of real-time non-interactive cutscenes and with dialogue during the main game.
Gears of War has two downloadable packs available. The first content available is a map pack that introduces two maps into the multiplayer mode: Raven Down, and Old Bones. The second download makes some changes to the game while introducing a new competitive king-of-the-hill type multiplayer mode called Annex.