As I mentioned in a blog of mine here in the community at www.complexitygaming.com, I discovered an indie space coop RTS upon my browsing throughout the internet, looking for anything interesting to come along. This game focuses on 1-8 player coop, and is really quite the game when you have a spare friend to try it out with you.
While it isn't heavy on graphics (has some current-gen backgrounds/etc.), it makes it up with large amounts of ships, both ship types and the amount they can be deployed in, along with some great AI to pair it up. Coincidentally, AI War can run on pretty much any decent computer (including mine) and can do it well--thousands of ships (30K+/10-120 planets) can exist in a single game, and its normal to have a couple thousand on a single planet in combat. The different ship types, combined with their own unique abilities and weapons, creates a diverse experience. The game focuses on the point of "little macro", where your own ships make smart targeting decisions and they never seem to overkill.
What do you do in the game? Fight off two customizable enemy AIs that seek to annihilate you, of course! It's why some claim it is a "4X Grand RTS/Tower Defense" because of the scale and diversification between units. While each player begins the game with a different type of ship specialization, along with four base ships, they can always obtain more of these ships through research by acquiring a higher tier level (they have separate unit caps, so you'll usually use T1's even if you have T3). There are other objectives in the game too, such as research raiding (all planets can be 'harvested' for knowledge), and capturing Advanced Research Stations which provide the entire team with a random ship type.
The economy in the game works similarly in comparison to modern RTS's: metal, crystal, and energy are the three main currencies of the game. You can acquire more through colonization; however, be warned that the AI will respond in kind when its "AI Progress" increases for either when you destroy certain structures, or do nothing (passive). It begins sending in larger and more frequent waves and cross-planet-attacks, so you always have to plan strategically if you wish to mitigate its efforts against you. Of course, if you are like me, you could capture every single planet and mass up all the different types of turrets to guard the wormholes where units travel through, then annihilate it even further--though your friend might not like it when he/she is not prepared for a thousand+ ships incoming.
Teamwork is the key here, and it's always best to play with at least one other friend because there currently isn't a teammate AI to play with--however, suggestions are always being considered by the developer, Chris Park of Arcen Games, and he stays close to the community. Many of these suggestions are implemented into the game, and are notably done with care with respect to the game. Always ready to help answer questions and give his thanks, he is the gem of the game.
For the duration of the Steam Holiday Discounts, AI War is being sold at 50% off, which means $9.99 USD only. With expansions coming out soon (most current would be the Zenith Remnant), it's a great cease. I say definitely try the game out if you have the time--you can play the demo for three hours in each of your games until you are ready to buy the full game. It doesn't include any DRM--only a simple license key; after consideration, Chris believes people will make the right decision, and treat the players with respect.