Average to the last
If you're not familiar with the setting, it's a fairly typical post-apocalyptic setting, where the survivors of Earth have been trapped (or taken refuge, depending on which point of view you're taking) on a floating city called the Ark, to escape the rising waters, presumably caused by global warming melting the ice caps and flooding the world. An semi-interesting plot, but that's about as far as this game gets into any semblance of a story.
The missions, of which there are eight, are the same whether you play them from the Security (aimed at protecting the Ark and preserving the peace) faction, or the Resistance (aimed at escaping the powers that be), and the objectives merely change depending on which side you're on. The teams each have eight members, and they can switch between any of the games four classes at will, depending on what is needed.
However, the classes are so similar, and their variations so minute, especially before you begin to level up and gain skills for them, that you often forget what class you're playing as until you realize you can't perform one of the very select and limited class-specific actions. Surprisingly enough, neither body type nor gun selection is dependent on class either, so that further deepens the lack of class variation.
There is a modest amount of character customization that varies widely between security and resistance, but basically, no matter what you do, on security you're going to look like a cop, and on resistance you're going to look like a thug with tires duct-taped to you.
The missions carry even fewer variation between them, and pretty much follow one of three variations of objectives:
-Destroy/Protect
-Escort/Defend
-Snatch and grab/Prevent
The maps are big enough to allow you some freedom of approach to objectives, but in the end, the objectives are always in the same place, so there's often not a lot of point to being creative. In fact, if you spend enough time on secondary objectives like stealing command posts behind enemy lines, you'll probably not be providing the kind of support your team mates need to complete the main objective(s), so even that becomes fairly trivial in nature.
The gun play is probably the best feature of the game. The guns, for the most part, feel pretty relevant. There is also a respectably large collection of guns (which grows larger as you level up and complete the various challenge maps), however, aside from the cosmetic differences from one gun to the next, you can hardly tell the difference from one weapon to the next within the major categories. I.e. all sub machine guns, despite slight differences in their damage, range, rate of fire and accuracy ratings feel pretty much the same. All shotguns, pistols, etc. pretty much follow the same way. Some guns are drastically underpowered, like the .50 cal mini-gun and heavy mg's, which have 100-200 rounds in their clips... but take 20-30 rounds to down someone... As opposed to a 9mm submachine gun, which can 3-shot someone. Unbalanced much?
Weapons also come with a minor amount of customization options, but these are mostly cosmetic, and generally pointless. For instance, you can throw a silencer/suppressor on a gun, but the advantage you may gain from being more stealthy is lost on the pretty drastic loss of firepower (which isn't realistic anyway...). You can attach extended magazines to a weapon to increase the size of their clips, but you take a loss on reload time. Throwing a scope on a weapon makes it take longer to equip, etc. Customization that involves such bald-faced give and take sacrifice mechanics really eats into the value of that customization.
Explosives are also chronically underpowered, with grenades and grenade launchers alike failing to kill enemies at point blank range.
The circle is completed by the game's brevity, which, in the hands of even a decent first person shooter gamer, will only take about four hours to complete BOTH campaigns.
The game is not bad, but its lack of polishing and depth is very unequal to how much the game was hyped.
Average to the last.