Army of Two is a fun game. It has an excellent combat system, good weapon selections and a nice amount of customization combined with a campaign designed with two people in mind for every section.
Graphically the game is top-notch and is one of the better looking games for the Xbox 360. The sound effects are on par with what you would expect from a shooter and the voice acting, while a bit over the top is still pretty good and entertaining.
The premise of the game is that you play Salem or Rios, mercenaries for a private military corporation, and set out on missions with one purpose in mind.... money. The story is pretty straight forward and while it throws some twists in there, they are generally very obvious and the characters and cutscenes give away too much too early that make it all very predictable. That being said, it's still a fun story to play through.
Unfortunately, some things feel a little rushed about the game. The campaign is short. Too short. For a game with such a heavy emphasis on co-op, there should have been more to the campaign. On Recruit (easy) difficulty, you could finish the campaign within a few hours. On Professional (hard) it might take you 6-8 hours. On top of that, while you are given primary and secondary objectives on missions, generally it feels like you are forced to complete all of the objectives or at least not given much choice in what you complete and don't complete. This game would have benefitted greatly from a branching story-line approach similar to that of Splinter Cell: Double Agent. Why not give you choices that actually effect the story one way or the other?
The weapon customization is a cool feature as well, but again it feels a little rushed. While most of the weapons have unique looks to them and various barrels and stocks look significantly different, there's no real "choice" being given. You have to buy parts in order. If you want "Barrel 3" you have to buy "Barrel 2" and first "Barrel 1". There's almost no reason to stop at "Barrel 2" unless you want a weaker gun (there is some logic to using a weaker gun, but it generally doesn't matter). All of the assault rifles have the same lines of upgrade: barrel, front attachment, stock, suppressor, shield, clip, appearance. It would have been nice to see more variety based on the specific gun. It would also have been nice to see ammo choices. Appearance is probably the most disapointing of the customizations as your only choice is regular or "pimped". Some of the "pimped" variations look good. But most of them are just heavy gold plating that makes you look a bit ridiculous. More time should have been spent in this area and there really should have been individual part appearance customizations. Maybe I only want a gold plated barrel? Maybe I only want a gold plated shield? It would have been nice to have been given that option.
Enemy AI is pretty good. The enemies will try to flank you and will try to flush you out with grenades. The partner AI is average and generally your partner will do what you want him to, but a little more refinement would help and it would have been nice to be able to give your partner specific locations to move to, rather than just follow, advance or hold.
The adversarial mode is poorly implemented. EA should have left it out completely and gave us a couple more co-op campaign levels instead. Basically adverserial mode consists of two teams of two in a deathmatch-like setup. The catch is, there are objectives and AI enemies on the level as well. Matches tend to turn into both teams meeting near an objective and fighting until one team is left standing. The team alive tries to complete the objective before the other team respawns. Otherwise, they clash again and try again. Rinse and repeat. It wouldn't be bad, but more often than not, you'll wind up getting close to the other team and fighting it out with your fists. The winner of a melee constant also seems to be a bit sporadic and often times you'll find yourself confused as to why you went down and your opponent didn't.
Overall the game is fun. It is a great co-op appearance even if it is short lived. Ultimately, unless you have Xbox Live and a friend to play with, its not worth buying and even then it is probably better as a rental.