Unlike MIA FPS XCOM, XCOM: Enemy Unknown is a spiritual successor to the classic PC strategy title. But old-school fans might be skeptical, so a newly-released demo should give you a chance to judge it for yourself.
The demo is now available on Steam, offering the first two tutorial stages. You'll be walked through combat controls and tactics, and then take a look around the XCOM base where soldier training and research takes place.
As a reminder, Enemy Unknown does offer the now-standard pre-order bonus. The Elite Soldier pack includes a soldier modeled after the classic X-COM: UFO Defense, Hyperion and Reaper armor kits for soldiers, and extra colors and tints to customize the squad. You could also snag the special edition to get an art book, poster, insignia patch, and digital bonuses including a soundtrack.