At first this looked like a cheap HL2 mod to me, but now that I have tried the demo I see it in all its glory.

The AI director really makes a difference, it's difficult to imagine without playing it yourself but the AI can be a real biatch. On my 1st play through I didn't think of it as anything special. But I began to realize its true nature already on my 2nd run as I was staying a bit behind and was sucked in by "a smoker" with the long tongue while my team further ahead was confronted by a horde of walking dead making them unable to help me. Similar "accidents" followed. It is simply brilliant and keeps the game fresh.

The atmosphere is the main selling point of the game tho, the grainy graphics, movie-like opening cinematic and brilliant sounds all contribute to it. The blood effects when blowing off the heads of the walking dead don't leave much to improve either. The graphics are undeniably a bit old, but the animation when your wounded team-mate is limping around are great and honestly the number of enemies on the screen at once reminds you how impressive the engine actually is.

The gameplay while rather simple seems to perfect the FPS formula, enemies are taken down with a single shot while you can take a fair deal of damage, not much glitches are around, weapons are varied and behave the way you'd expect them tho, pipe-bombs attract zombies leading to mega-kills while under-powered pistols never run out of ammo, every weapon has its use.

Pacing has always been the strenght of all Valve games, and it's still intact in L4D despite the dynamic structure of the game. Zombie hordes will break the silence and the boss enemies will surprise you in ways you can't predict.

If I had to come up with something negative to say I guess I could blame the AI team-mates for being too smart, they never make mistakes and as such make the experience a lot less exciting, thankfully finding human company is no problem. Other issue would be the rather dated source engine, the graphics despite being stylished and fitting to the theme can't always hold up to modern standards.

But all in all, I ordered this game tonight judged by the demo, and I recommend you atleast give the demo a try as well. And remember, even if the demo only gives you few hours of fun the full game will have A LOT more content.