After a few delays and epic shit-tons of anticipation, the early access demo for Left 4 Dead 2 dropped for pre-purchasers. I'm a pretty big fan of the original, so please allow me to throw my two cents in regarding our glimpse of the sequel.
The demo lets you play through two chapters of the final campaign (about twenty to twenty-five minutes of gameplay or about 1/12 of a single run through the total game). My conclusion: L4D2 is everything we want out of a sequel--more of everything that worked in the original, less of what didn't work, and new and inventive additions. And let me also address the naysayers: we could not have gotten this game by incrementing through free downloadable content. This is a totally new game with vast improvements, so quit your goddamn bitching!
The key to this game is "more". More campaigns, more gameplay modes, more enemies, more variety in both your weapons and your enemies, more story, more well-rounded characters, etc, etc, etc. And all that "more" mostly works. I will say that the demo never felt like it got bogged down by the additions--and we weren't all veterans playing either. We had someone over that had never played the first one; we gave him a quick tutorial on the gameplay and by the end of the first chapter, he was keeping up and killing things alongside the rest of us.
My only real complaint, and I hesitate to call it a "complaint", is with the new Special Infected. I like them, I just found them a bit underwhelming. The Spitter feels like a less-dangerous Boomer. The Charger feels like a less-dangerous Tank. The Jockey feels like a less-dangerous hybrid between a Hunter and a Smoker. The Wandering Witch behaves just like a regular Witch, only now she can't block off paths, making her much more avoidable. Coupled with the inclusion of the old SI's, the new ones gave us variety, but not much of a challenge.
The addition of Uncommon-Common Infected certainly made up for it. So far I've only gotten to play against the riot-gear-wearing infected, who are more or less immune to a frontal attack. Having those mixed in with the normal horde did a lot to spice up gameplay, and I'm supremely interested to see how the different UCI's add to the challenge and character of the levels they inhabit.
The really dramatic improvement of this game over its predecessor comes from the weapons. In the original game, you had a shotgun, an Uzi, or a pistol, and could eventually find an automatic shotgun, an assault rifle, a hunting rifle, and dual-wielded pistols. 98% of players go with either the shotgun or the automatic (whichever version of either that they happen to have handy), with pistols as a backup. Since all guns are found grouped into caches, everyone just goes straight to their favorite.
The L4D2 guns are far more organically placed, forcing players to occasionally use a gun they don't prefer. Additionally, there are many different types of each class of gun. We encountered two different pistols, three assault rifles, two handheld fully-automatics, and three shotguns--each with its own unique character. Furthermore, rather than having your secondary weapon be a pistol, you can swap it out for any number of melee weapons, everything from a cricket bat to a frying pan to an electric guitar. I was skeptical at first--would I really want to forgo dual-pistols just so I could wield a melee weapon?
Then I tried out the machete. After I picked that up, I barely even fired my primary weapon. Hacking the infected to pieces was just too much fun.
There's also a "bile bomb" (Boomer puke, essentially) that can summon the horde to attack whatever you throw it at--which is interesting and great for bringing down Tanks. It's not quite as cool as the plain old pipe bomb, which attracts infected and then sends bits of them flying every which way (as opposed to vaporizing them like the original game... pipe bombs are so much fun to watch now).
So, all told, I was looking forward to playing L4D2, and now my appetite has been whetted. It looks to be a dramatic improvement over what was already a fantastic game. I'm excited.