A overall fun action game, which seamlessly blends platforming, FPS, and fighting game qualities.
Pull the left and right trigger simultaneously to activate your weapon's energy shield, capible of absorbing energy and melee attacks, although explosives will still do some damage.
Couple that with the ability to double jump, and to spring off of walls and other vertical surfaces, and you have a controlled chaos of swords, rockets, lasers, and, of course, dismembered body parts (staying true to the Unreal Tournament dynasty).
An extreme change from previous unreal games is the weapon system. A player can only carry his/her standard pistols, a energy weapon, and an explosive in the entire match, and weapons are chosen previous to combat. This leads to becoming attached to a single set of weapons, while knowing practically nothing about the others. Of course, a veteran player will be versed in all sets, as to exploit the weaknesses of the reaper's toys.
Weapons are varied very widely, from the saw-blade launching Ripjack, to the lifeform launching Biorifile. The latter is a very interesting idea; a gun that fires sentient blobs that hop toward a target. It can be charged to launch a larger, more damaging blob.
And my favorite, the amazing (for lack of a better word) "trimary" fire. Giving you a third style of devestation, this is an innovative item indeed. As an example, the rocket launcher fires a single rocket with a tug of right trigger. Hold left trigger and you can load three rockets, and as the final warhead is loaded, they launch. But, while still holding left trigger, if you were to tap right trigger, the three rockets split into six spiraling rockets, allowing much more area to be covered, but the same amount of ammo to be used.
There are many more little cookies to do in this game, like the ability to use the pistol's secondary fire to stun your opponent, then using a melee weapon to do a Mortal Kombat style fatility, ordered button tapping and all.
And on the topic of Mortal Kombat, let me just add that due to the Midway ownership, there is a secret character who is guarenteed to "shock" you.