The best parts of Half Life 2 crammed into three hours.
Forget all the naff sequences of HL2; the boring characterisation sequences, the inane vehicles and the continuous fleeing. Instead you get to wander through what seems like miles of pitch black Zombie infested carpark with only your torchlight and Alyx Vance to hold your back. You then get to essentially raid Combine HQ, killing more Overwatch troops then were contained in the entire original game before getting to lob rockets everywhere at Striders.
The game manages to skillfully do away with any real plot- all you gotta do is get the hell out of Dodge before the reactor thing goes off and blows City 17 sky high. The AI, both enemy and friendly is faultless. Enemies will use cover before trying to overwhelm you with their huge numbers, Zombies hide in dark corners ready to spring an ambush on you and Alyx Vance ends up operating like an unstoppable killing machine (occasionally kneeing zombies in the groin which is alway hilarious).
The only problem is that when I thought I was a quarter of the way through the first half of the game I was already finished. I only hope that when they finally get around to releasing Episode Three that it will be as awesome as this game was. Forget HL2, this one's the real classic.