Key features of the game include:

* Assault Mode: The much heralded single-player oriented gametype returns with all-out battles with land, space and air-based vehicles on the home worlds of various Unreal Tournament 2004 combatants. In one scenario, players will experience the adrenaline rush of space-based battle while attacking or defending a Skaarj mother ship. Another scenario takes place on Xan Kriegor's mechanical home world where players attack or defend a robot construction factory. There are currently six Assault scenarios planned to ship with the game.
* Onslaught Mode: New multi-player oriented combat game type on custom-built large-scale maps featuring awesome new weapons and land- and air-based vehicles. From the lethal bomber to the nefarious spider mines - players will work as teams to control map points and win the conflict. There are currently nine Onslaught maps planned to ship with the game.
* Live voice chat over LAN and internet with 3D audio (on supported sound cards) so players can sense where voices emanate from. Using a microphone and headset (not included), players can communicate with teammates and buddies or just yell at everybody who gets in their way! Several settings are provided to allow users to customize their voice chat experience.
* Fan-favorite Unreal characters will return to challenge in the tournaments, including the Skaarj, the Necris and the infamous Xan Kriegor.
* The game will include 20 never-before-seen maps for the existing game types, featuring tons of new textures, new static meshes and new music. It's a field day for mod makers! Also included are new maps from Digital Extremes designed specifically to appeal to "hardcore" UT players.
* In total, Unreal Tournament 2004 will ship with more never-before-seen maps than the entire number of maps that shipped with Unreal Tournament 2003!
* UnrealTV match broadcast system will allow for hundreds of people to view an Unreal Tournament 2004 match with minimal performance impact on game
server. UnrealTV will be fully integrated into the server browser to make it easy to located broadcasted matches.
* Complete end-user voting system that will allow users to choose game type, maps, mutators, rules and settings and will also provide the ability to remove troublesome players from the game. Custom clan-match voting system will allow clans to negotiate acceptable game settings prior to a competitive match.
* Unreal Tournament 2004 users will be able to join games on Unreal Tournament 2003 servers.
* A completely redesigned user interface (UI) will be easier to navigate and support context-sensitive menus, an in-game login menu (to improve team balancing) and an improved server browser with enhanced server filtering options. The underlying user interface system has been reengineered to be easier for Mod authors to build menus and implement their own UI designs.
* Tons of cool gameplay tweaks and refinements including unique crosshairs for each weapon, the ability to carry dual Assault Rifles, improved computer-controlled "Bot" team coordination and movement, network bandwidth usage optimizations and more!