Full Story:
NEW GAMETYPES:
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.

NEW MAPS:
10 new maps are including, spanning all game types, including Deathmatch, Double Domination, Bombing Run and Capture the Flag. The new areas include additional textures and static meshes that can be used with the Unreal Editor. Maps include DM-IronDeity, DM-IceTomb, BR-Canyon, DOM-Junkyard, DM-Rustatorium, DM-1on1-Crash, DM-1on1-Mixer, DM-Injector, CTF-Avaris and CTF-DoubleDammage

NEW ADRENALINE COMBOS:
The two new adrenaline combos can be added using mutators:

Pint-Sized: Makes the player half their normal height (but players can no longer crouch).

Camouflage: Places a holographic projection of a static decoration over you as a disguise. The projection doesn't quite extend to your feet, so you have to crouch to be fully concealed.

OTHER NEW FEATURES:
Announcer Voice Options: Several new announcer voice options are now available

Music Options: This bonus pack also includes a new OGGPlayer that gives gamers direct control over the music that is played during the game.