Titanfall is a first-person multiplayer shooter for up to twelve players simultaneously. Set on a war-torn planet with two factions (Interstellar Manufacturing Corporation (IMC) and the Militia), it features battles between pilots on foot or boarding large mech-style Titans. The game can be played in six game modes: Attrition (team deathmatch with hostage rescuers against kidnappers), Capture the Flag, Hardpoint (capture and hold three locations), Last Titan Standing (last player alive wins, all players start in a Titan), Pilot Hunter (score for the team by killing pilots, not Titans - at the end of the match there is an epilogue where respawns are disabled and the losing team needs to reach an evacuation point/dropship for additional experience points), and Variety Pack (mix of all game modes). There is also a Campaign mode for each faction with a mix of different game modes and bits of story between each mission.

The game is fast-paced and while on foot pilots are able to wall jump and link jumps in a parkour style using a jet-boosted belt. In a general game players start by choosing a pilot type. Some of the available weapons include assault rifles, SMGs, shotguns, sniper rifles and smart pistols. During the match a timer counts down (generally three minutes) until a Titan can be deployed. The timer countdown can be shortened by killing other players. When a Titan drops down from the sky a pilot can board it. Playing as a Titan has completely different movement, but it is still agile. The pilot's double jump is for instance replaced by a dash as a Titan cannot jump, crouch or seek cover. A Titan has very different weapons and is much stronger to take on other Titans. It can be ejected at any time when under attack and it is possible to issue commands to have it follow or guard you. Other players can attempt to board and throw out a player. These can be repelled by activating electric smoke and a Titan has also distinct abilities such as the vortex blocker to stop incoming projectiles, gather them and return them in midair. It is also possible to crush pilots. When a Titan is destroyed a new countdown timer is started.

Other game elements include burn cards (up to three per match) for temporary power-ups and AI-controlled minions with three types: grunts, marvins and spectres. The game has a persistent experience system and pilots can level up. This influences for instance the loadouts for both pilots and Titans prior to each match. The available slots for pilots offer room a primary weapon with mod and/or attachment, an anti-Titan weapon, sidearm, tactical ability (for instance cloak, stim or active radar pulse) and kits with specific abilities for different tiers. For a Titan the loadout consists of the chassis, primary weapon with mod, tactical ability, ordinance weapon and different kits.