You'd assume playing with a real person would make things easier, but if anything it's actually harder. When playing with an AI partner you know where you stand. Although there's no command to move to a certain location (a big omission in our book), you can tell him to tag along with you, head on into the level or hold firm by pressing left, up or right on the d-pad respectively. The key to making the best use of your AI partner is deciding when to switch between the aggressive and passive modes for each of these commands. Passive makes him take cover and generally try not to get the attention of enemies, while aggressive sees him taking more risks and making sure the enemy knows he's there - effectively taking the aggro.
By using the on-screen mini-window which shows your partner's position you can pretty effectively move him to the position you want. Tell him to move through the level and then switch to an aggressive hold firm command when enemies are in sight, and he'll do his job. With the aggro on him you can sneak around the side and take out enemies relatively easily. If he starts to take too much heavy fire, a quick tap again right on the d-pad will tell him to play it safe, so he stops firing and takes better cover. You can then take the aggro and give him time to recover. At times it works well, but it's a flawed system with its success depending on the number of enemies and their willingness to rush at you.
With a real partner things aren't as clear cut. The same rules apply, but you've got to work together, with clear roles defined at every encounter and communication needing to be spot on. If you find yourself playing with someone with considerably less ability than you, you might as well forget about it as you'll both be killed, over and over again. When you're shot down you usually get a chance to be given medical aid (unless you take a shotgun to the face), with your partner running in and fixing you up, hopefully before your time is up. Doing this in the open isn't ideal so you're able to drag your partner behind cover - something I found the AI was far better at, despite coming unstuck by grenades on numerous occasions.
Other co-op actions seem great at first but soon become less and less used as you realise you're better off sticking to what you know. Using a shield and working as a team behind it is ok, but it limits your attacking options, and the co-op sniping is something we found very little use for. You'll be forced to use the back to back move at various points (at least once per level) but it feels rather tacked on. You simply spin round and shoot while a tonne of enemies run at you. These set-pieces could have been cut from the game at no real cost. You'll also have to help one another up onto ledges at various points, but at no point did the game feel especially better as a co-op game than any of the others on the market.
All of the problems are compounded by some dull level design and a lack of variety. Every level plays out the same with the final guy needing to be flanked and shot from behind. Given that a number of these areas are little more than outdoor corridors, finding a path around the back without running straight past the super enemy is practically impossible and it ruins the illusion that you're actually outthinking your foe.
Never before in a game have I witnessed so much anger by two people playing together. At times Army of Two makes enjoying it impossible, with the game seemingly trying its hardest to ruin the potential it has. Add some annoyingly placed checkpoints to the list of problems and you have a game that only the most committed will work through - even though it can be finished in six hours on the highest difficulty available from the start. Hovercraft sections are introduced at a number of points, no doubt to spice the gameplay up a little, but they feel dated even compared to the boat sections in Half-Life 2. Throughout the campaign I was waiting for things to kick off and for the game to go up a gear, but the spectacle never came.
When you first use a parachute, sniping enemies below while your partner controls the chute's descent, you get a flash of something brilliant, but later sections make aiming nearly impossible and you can simply fly past most the enemies anyway, making the shooting a diversion at best. You can even perform ridiculous air guitar solos or high fives with your buddy, but they're completely bizarre in the context of the game and largely pointless.