This is a 4-player 2v2 map in Supreme Commander 2.This map has four bases, each seperated by an island. The reason it is called Mirror Island is because in strategic view the two sides are mirror images of each other. Each player starts out on a base plateau with large walls, similar to the Clarke Training Center. they are free to build their base on the plaeau and on the walls, too. In the center of the map there is a large water basin, helpful for naval players as this allows you to move your shpis in to bombard the enemy base with tactical missiles and cybran laser guns.
If you are Illuminate, do not hesitate to buy the Space Temple, as fielding huge land armies can be difficult on a map of this size. Simply put the exit to the space temple just outside your enemy's vision, send your land armies through and then when the cooldown timer ends, move the exit point back to your base. This will allow you to send huge land armies if you are a land-based player, like me. The same can be achieved with Transport Aircraft.
Sometimes sending your ACU to the back of your base is a good idea, if the enemies decide to use land, as there is only one entrance to each base. And, your enemies will have to pound through your factories and mass extractors to get to your ACU.
This map is amazing for Naval-based players, as they can cluster outside the enemy base and bombard them with bullets. Yet another helpful strategy is to build one or two Command-class or Atlantis II Aircraft Carriers, send them out of range of the enemy base, and mass-produce bombers and gunships. Then, when the time comes, move the vehicle closer and release your army. This can also be done early-out in the game to have a fast-paced game.