One of the most Underrated games out there, still doesnt get recognition for the incredible gameplay/multiplayer inside.
It's singleplayer has NO story whatsoever and is not supposed to. Its merely practice for you when you go up against other human players. Thats where the game gets fun. With such complex yet flowing maps, players blast through corridoors and outdoor settings pumelling enemies with firepower that leaves you shaking.
The guns have an excellent balance providing powerful weapons for the more less skilled players, like the Flak Cannon or Rocket Launcher and much more difficult to use but devastating guns like the Bio Rifle and Shock Rifle.
The cast array of game types brings a good mix of gameplay, each different from the other. You could pit your team of friends against another human team or custom build a devastating unit of bots to challenge the best FPS players around the world.
The addition of mods like the Rocket Arena, Insta-gib etc. force players to use the cover accordingly. For example, when facing a sniper or insta gib, a little shuffle left right is more than enough to avoid damage. But if you are staring down the barrel of a Flak Canon with an enforcer (pistol) in hand, RUN!!!
This is a multiplayer game that has to be part of every gamer's collection.