Enemy unknown.. unless, y'know, you played the original games.
X-COM: Enemy Unknown is the game that X-COM fans collectively wished would be made when X-COM first person shooter was announced: a turn-based, tactical squad-based strategy game with deep ties to the X-COM PC legacy. Ironically, a 2K P.R. representative told me that Firaxis' Enemy Unknown had been in development for several years before the FPS X-COM game being developed by 2K Marin was announced. At E3, 2K has been showing the game in a theatrical setting, showcasing the enemies and high-end abilities of the available squad members near the end of the game.
The presentation begins with the careful movement of a tactical squad already in position. Then the enemies are introduced, starting with the nefarious chryssalid, whose one-hit-kill starts the bloodbath that drops a team of five or six down to one in a single turn, and the soldier downed by the chryssalid is turned into one after dying. When the surviving member of the squad calls for evac, control sends in a Reaper Squad, who over the course of the war with the aliens have become more than human.
As a great joke, the Firaxis development team made the Reaper Squad commander Sid Meier, with a detailed character model. The Meier-commander uses mind control to take control of one of the enemy units to force him to drop an armed grenade at his feet, exploding himself. A jet-packed Sniper floats high above the scene to take out one chryssalid, and then with a bonus shot for delivering a critical hit, takes out the second. The final Reaper uses Ghost Armor to make himself invisible, zip up to the top of a building to take out the last alien, a Berserker, finishing the fight. Tit-for-tat, a turn later the enemies have been reduced to nothing by a tight tactical offensive.
The presentation highlighted how the game's turn-based tactical gameplay and careful use of character roles can lead to success, as well as showing off just how cool your squad can become in rising from a lowly band of humans on the run from the invading aliens to hunters themselves.
X-COM: Enemy Unknown looks like a great refocusing of the brand on the series' roots. It's slated to be released on PC, Xbox 360, and PS3 on October 9th, 2012.