There are currently seven default modes of combat in Unreal Tournament 2004. Additional game modes may be added as development nears completion.

Assault (New in UT2004)
Assault mode returns! Redesigned for UT2004, this fan-favorite mode sees teams face-off to defend and attack fortified bases, from fast-moving trains, barreling across an arid alien desert to a Skaarj mother ship, poised to attack the human home world.

Onslaught (New in UT2004)
Onslaught mode takes team combat to the next level! Opposing teams are pitted against each other to capture and hold strategic points in order to attack and destroy the enemy power core. Taking place in massive outdoor environments, here is where vehicular combat comes into its own. Flying and driving machines take combatants to the frontline and gigantic mobile battle stations serve as a platform from which to launch devastating attacks.

Deathmatch
Players are pitted against each other in a balls-to-the-wall free-for-all. Anything goes. The one with the most kills wins.

Team Deathmatch
Join your teammates in the quest for battlefield supremacy. The team that kills the most enemy players is judged the winner.

Capture The Flag
Each level has two team flags. In order to score, one team must penetrate the opposing team's defenses, 'Capture the Flag' and return it to their home team's flag. If the flag carrier is killed, the flag drops to the ground for anyone to pick up. If your team's flag is taken, it must be returned before your team can take the opposing team's flag.

Double Domination
Each level has 2 Domination Points. In order to score, you must 'capture' each Control Point (by running over it) and keep them in your team's possession for 10 seconds. After scoring, the Control Points reset to neutral and will become available to Dominate again after another 10 seconds.

Bombing Run
Each level has one ball in the middle of the play field. The objective is to pick up the ball, deliver it to the enemy base and fire it through their goal. You must also defend your own goal to prevent the enemy from scoring. The ball is dropped when a player is killed and can then be picked up by anyone on either team.

Mutant
The player who makes the first frag becomes the mutant and is immediately equipped with all weapons, extra ammo, invisibility, agility and berserk. However, the mutant's health slowly decreases and can only be replenished by fragging other players. Once there is a "mutant," all other players are charged with hunting him down. Points are scored only by the mutant when they frag other players. As an optional twist, the player with the lowest score becomes the BottomFeeder -- he can frag other players who are not the mutant and receive points. As soon as his score isn't the lowest, a new player becomes the BottomFeeder.

Last Man Standing
This is similar to the Last Man Standing mode in the original Unreal Tournament. Players regenerate health when they frag an opponent. If a player stands in one place for too long, they will be revealed to other players as a camper and their location will appear on all opponent's displays.

Invasion
In this game type, players band together to defend against waves of incoming monsters -- including many of the monsters from the original Unreal. Players cannot respawn if they die during a wave, but as long as one player makes it to the end of a wave alive, everyone respawns for the next wave.