In the level we played, mercs and seriously good bros, Salem and Rios, were fighting their way through the streets of Shanghai, on their way to the city zoo -- a standout level from the console game. We controlled one of the two while the CPU backed us up, but the game does support local, ad hoc co-op.
The controls were dead simple: Move with the analog stick, shoot in eight directions using a combination of the four face buttons. (Yes, it's a dual stick shooter, more or less.) It's also possible to crouch and roll (handy for ducking and evading enemy fire) and make use of the copious amount of cover the stages offer. As in the console game, players can issue commands to their partner to advance, stay put, get aggressive or get sneaky.
The command system worked, but given the rapid arcade-style pacing of the action it was sometimes hard to even remember (or want to use) the orders to any degree. As we carved a path toward the zoo, wave upon wave of 40th Day soldiers came at us -- most simply shooting, others manning turrets and a few heavies that required some strategy to bring down.
This is where those buddy commands actually worked quite well. Faced with a flame thrower heavy, we told our AI amigo to go on the offensive, which raised his Aggro meter and made us virtually invisible to the enemy, who we were able to flank and shoot his tanks until he exploded. The tactic also worked well against enemies on turrets and yetis. (OK, so we made that last one up.)
We collected a lot of money pick-ups along the way, which will be used to buy things from weapons dealers in the final game. There are also temporary power-ups that increase the killing power of current weapons, for example.
Our time with the game was limited to a rather small section of one level, but it was still enough to make us fans of the unique art direction and use of the Aggro mechanic in a game of this type. We're hoping the final version offers up more variety in its stages, though, especially plenty of larger setpiece events / encounters -- like the airliner that crashed right in front of us -- to keep things exciting.