If you haven't viewed the intro movie yet, I highly recommend that do.
I just played the demo for this, and I have to say that I was quite impressed. The gameplay was completely different from what I expected and the AI director really does a good job of keeping things interesting; I imagine that seeing witches and tanks in the same place every playthrough would make things immensely dull. Unlike in Doom 3 where I would often backtrack after every major skirmish to get ammo and/or health, backtracking in Left 4 Dead often just causes more zombies to spawn and results in an overall loss of health and ammo.
I really like the fact that pistol ammo is unlimited. This, combined with the fact that the game penalizes backtracking, forces you to continue pushing forward at a pretty steady rate while still keeping an eye out for bosses. Another thing that I really like about unlimited pistol ammo is that it eliminates the need for a melee weapon, and I'm certain that any melee weapon in this game would be absolutely worthless.
I really like the way that the boss zombies work and the way that they force team play. It's frustrating when you're playing with people for the first time (I really hated smokers) and you're yelling over the mic for people to rescue you, but I think that in the long run it should improve the game's replayability (which is really what it's all about).
Another cooperative element that I really like is the way that health packs work. I never really was fond of the whole "touch medkit, receive health" that encouraged people to camp beside health in firefights and then strafe onto it after taking damage. The way health packs work in Left 4 Dead is realistic, but more importantly it forces you to be completely on the same page with your team, whether it comes to exchanging health or simply covering someone while they apply bandages.
The main gripe I have about the game so far is the primary weapons and balance. There's no reason to ever use any weapon that's not a shotgun, and the auto shotgun borders on broken in my opinion; you get an incredibly powerful close-range weapon with a high rate of fire and virtually no worries about ever running out of ammo. The automatic weapons are nice for long range, but usually when you're shooting at long range it's to kill enemies that haven't been alerted to your presence, and in that case you could just use the pistol. The same goes for the hunting rifle to a lesser extent, although I can see that being useful if you have a really cohesive team that is able to cover your sniper. The only thing that I really believe keeps the non-shotgun weapons from being useless is the lack of spread; if you're trying to shoot enemies away from a teammate, using a weapon with high spread is probably not the best idea.
One thing I noticed in the game is that the "push" command is very spammable, I found in a lot of situations I could just dive into a fray and spam push and let my teammates get kills without taking too much damage. (I also did this a lot after allowing myself to fall victim to the boomer's bile, which happened on more than one occasion.) I'm not sure if this is the way that Valve intended it to work; I guess it works pretty well since it's something that would either have to be very useful or near worthless.
I wasn't planning on buying this game immediately after it came out simply due to the cost (I don't think Valve has ever released a multiplayer game that had a launch price as high as $50), but depending on how the finished product turns out, I may buy it. Knowing Valve, there will almost certainly be periodic updates to add new maps, and the addition of new weapons and new boss zombies several months down the line isn't outside the realm of possibility either. That's why I love Valve.
I just played the demo for this, and I have to say that I was quite impressed. The gameplay was completely different from what I expected and the AI director really does a good job of keeping things interesting; I imagine that seeing witches and tanks in the same place every playthrough would make things immensely dull. Unlike in Doom 3 where I would often backtrack after every major skirmish to get ammo and/or health, backtracking in Left 4 Dead often just causes more zombies to spawn and results in an overall loss of health and ammo.
I really like the fact that pistol ammo is unlimited. This, combined with the fact that the game penalizes backtracking, forces you to continue pushing forward at a pretty steady rate while still keeping an eye out for bosses. Another thing that I really like about unlimited pistol ammo is that it eliminates the need for a melee weapon, and I'm certain that any melee weapon in this game would be absolutely worthless.
I really like the way that the boss zombies work and the way that they force team play. It's frustrating when you're playing with people for the first time (I really hated smokers) and you're yelling over the mic for people to rescue you, but I think that in the long run it should improve the game's replayability (which is really what it's all about).
Another cooperative element that I really like is the way that health packs work. I never really was fond of the whole "touch medkit, receive health" that encouraged people to camp beside health in firefights and then strafe onto it after taking damage. The way health packs work in Left 4 Dead is realistic, but more importantly it forces you to be completely on the same page with your team, whether it comes to exchanging health or simply covering someone while they apply bandages.
The main gripe I have about the game so far is the primary weapons and balance. There's no reason to ever use any weapon that's not a shotgun, and the auto shotgun borders on broken in my opinion; you get an incredibly powerful close-range weapon with a high rate of fire and virtually no worries about ever running out of ammo. The automatic weapons are nice for long range, but usually when you're shooting at long range it's to kill enemies that haven't been alerted to your presence, and in that case you could just use the pistol. The same goes for the hunting rifle to a lesser extent, although I can see that being useful if you have a really cohesive team that is able to cover your sniper. The only thing that I really believe keeps the non-shotgun weapons from being useless is the lack of spread; if you're trying to shoot enemies away from a teammate, using a weapon with high spread is probably not the best idea.
One thing I noticed in the game is that the "push" command is very spammable, I found in a lot of situations I could just dive into a fray and spam push and let my teammates get kills without taking too much damage. (I also did this a lot after allowing myself to fall victim to the boomer's bile, which happened on more than one occasion.) I'm not sure if this is the way that Valve intended it to work; I guess it works pretty well since it's something that would either have to be very useful or near worthless.
I wasn't planning on buying this game immediately after it came out simply due to the cost (I don't think Valve has ever released a multiplayer game that had a launch price as high as $50), but depending on how the finished product turns out, I may buy it. Knowing Valve, there will almost certainly be periodic updates to add new maps, and the addition of new weapons and new boss zombies several months down the line isn't outside the realm of possibility either. That's why I love Valve.