Fallout: New Vegas is an action role-playing game that can be played from either a first-person or a third-person perspective.[1][2] It is set in the Mojave Desert, 204 years after a nuclear war that decimated much of the United States.[1] The player controls a courier who survived an attempted killing by an unknown assailant.[3] The goal of the game is to complete a series of quests to find the assailant; the game eventually culminates in a war between governing factions that are vying for control of the Mojave Desert.[4]: 67  In addition to the main quests, the player can participate in optional, unrelated side quests.[4]: 136  Kristinie Stiemer of IGN estimates completing every quest in the game takes around 100 hours.[1]
New Vegas features a freely explorable open world map.[1] The player can explore locations ranging from small settlements and abandoned buildings to large locations like the Hoover Dam and the city of New Vegas, which was built from the remnants of Las Vegas.[2][5] The player is equipped with the Pip-Boy 3000, a wearable computer that serves as a menu and allows them to access items they have acquired, view detailed character statistics and active quests, and look at the map.[6]: 6–10  The player can use the Pip-Boy 3000 map to fast travel to previously discovered locations, as a radio, and listen to songs from the 1940s to the early 1960s on makeshift radio broadcasts.[4]: 27 
The player can engage in combat with non-player characters (NPCs).[5] The weapons in the game include standard guns, energy-based guns, melee weapons, and explosives.[4]: 30  Guns can be equipped with additional modifications such as a scope.[5] While in combat, the player can use a gameplay mechanic known as VATS, which pauses the game and allows the player to target specific body parts of an enemy.[1] VATS is dictated by a statistic known as Action Points.[1] Attacks made using VATS cost Action Points; when the player runs out of Action Points, they must wait a short period before they can use VATS again.[1] Some NPCs can be recruited as companions, and will accompany the player and assist them in combat.[5]