Well my experience with the demo has been largely unhealthy.

I preordered, and so I had access to the early demo.

I took a half day off work to get home around 3:00pm to play the demo, because surely Valve would release the demo by then. Well they didn't, and when I went to sleep the official release time was "1:00 am CST" so I figured I'd wake up an hour early and get some time in with it.

Well they changed the time again to like 3:00 pm CST, so it would have to wait til after work.

Then they changed it to like 8:00 pm once I got home.

So eventually I get to play it, but the game is unplayable because of the uh, I forget which option it is, but Dual Processing or whichever is turned on and it destroys my performance.

But at the time I thought rebooting may work, and it turned into this huge thing where my compressed air nozzle got caught against something while trying to clean my case out with it and it got stuck behind the case fan, but hey I found my mechanical pencil that I lost months ago resting snugly on my video card, so I guess in the long run it helped.

So anyway it's still unplayable and I give up. Only later do I find by disabling that option that it becomes playable, but unfortunately now L4D2 demo frequently corrupts my graphics and I'm forced to reboot like 5 minutes into the demo. I've beaten it once (in single player) without having to reboot because of this graphics issue, and it does it consistently.

I am not pleased. 

4 delays in total, all so we can betatest for them, for free :P

But I wanted to discuss more about the gameplay since there's plenty of complaining to read elsewhere.

There's been quite a few updates to the demo and Steam, pertaining to the demo, over the past couple of days though - maybe your issues have been resolved. 

http://kotaku.com/5396591/play-versus-mode-in-the-left-4-dead-2-demo 

I saw that over on the forums, looks pretty neat - I saw a video of a charger making a double kill, so I guess it'll be weakened some.

Internally the game is wide open - in L4D1 you could play Verus via the console for the two campaigns that didn't have it. Just screwed up a handful of sphere maps.

I'm wondering if the backwards compatability feature that may or may not be included is possible now, before its released.

Copy and paste the maps and a command from the console. Maybe LoadMap. 

I do like the changes to tier 1 compared to the original. They've done something I always thought would make sense in l4d1, which is to make the sub-machine gun the weapon with the lasting supply of ammo. In the original the shotgun is much better in all combat bar vs a tank, but is also takes much longer to run out of ammo. Now you can't just use the shotgun throughout the first map, you have to make use of pistols too.

Making melee weapons replace the pistol slot seems like the best way to balance carrying one, much better than the rumour that you had to carry them like physics objects and drop them to draw a gun. Personally I love my pistols too much, especially now there's a magnum to consider, so I don't think I'll get much use out of them. Still, my opinion might change as I play more.

On backwards compatibility: I heard that the bsp format has changed between the games, which would mean playing old maps might take some work... 

Game looks promising, but to me it's really impossible to judge without proper versus, cause that's always been where the game really shines. 

Versus was the first game mode.

Problem with versus is you need to know the maps to play as infected - it puts alot of people off since whoever knows the map better wins.

Try

http://www.l4dmaps.com/

For L4D1 maps, if you haven't already. Coal'd Blood is great, Death Aboard quite good but could be better on level design, Death row is good, Night Terror is stupidly difficult, but has some nice themes (like Moria) Suicide Blitz is well made, but the rescue map is stupidly simple.

I tended to forget the crappy ones. Want to play the mushroom kingdom map though.

Melee weapons are great against hordes.

BSP remains the same AFAIK, I think what changes is the shader format. Stuff that gets broke appears as shiny silver - the sphere mapping.

Given the renderer change I'd guess a shader change is probably a given. But haven't done enough with source to know how flexible its shaders are. 

Just got around to playing it, just in single player mind, mainly so I could just take a leisurely stroll around and see what is new and different.

Was pleasantly surprised! The guns all feel great to use, especially the new magnum pistol. Melee weapons are great fun, and I couldn't help but burst into laughter as I looked back into a room and saw Coach with his trusty frying pan standing square in a doorway giving every last zombie a good battering.

Didn't really try any of the new pickups, but the boomer bile could be interesting. I guess whatever you throw it at get swarmed with zombies?

As for performance, I would say it runs at the same pace as L4D1 does on my ageing rig, which is great considering it looks 2 times as good!

Not to sure about the new infected yet, I guess it will take time to get to know and love them, the spitter seems incredibly weak, 1 or 2 shots and she dies! The Jockey is hilarious ("hey, I saw one of those little bastards!"). The Charger does what it says on the tin, but again it dies quite quickly!

Overall, I really like the game and will probably pick it up when it comes down in price. 

That's it pretty much, but don't think it'll help against a tank - he just smashes the commons aside. The witch as well just charges straight through them to whoever threw the thing.

I find its best just to throw it at the floor. Think of it as a L4D1 Pipe Bomb that doesn't explode.

Also, it seems like the witch can now change targets, though I'm not sure what the trigger condition is, maybe before she's hit anyone. 

The demo obviously.
Enjoyed it but I kept getting what I thought was terrible lag all the way through. It would play fine for 30 seconds and then freeze for 6-7 seconds continuously.
So I played through the level with three random people, which was fun despite the terrible problem.
On exiting I found that Windows Firewall had been blocking it the whole time (grrrrRRRRR!!!!!)
So I then clicked on the "unblock" button.
Havent tried again yet..... 

Is the demo public now or did you all pre-order? 

RickyT23 that is caused by Multicore Rendering (I believe.)

Go to video options -> advanced -> multicore rendering -> disabled.

BUT BE WARNED! There's a bug (or a feature) in the L4D2 demo that will TURN IT BACK ON EVERY TIME A LEVEL LOADS. So you will have to turn it off every time. 

I'm just a little disappointed the demo is so short. Could have been the entire campaign minus the finale... 

its unlocked for everyone now. I guess I have a crazy preconception that demos are for trialling the game before you buy =)

I should tell valve, as there might be others who feel the same way? 

please. 

Yep.

It's a big kick in the FJ's when you dupe yourself into pre-ordering. And the second kick is when a week or so into sales they have a 50% off weekend. 

If I play TF2 I get to wear a hat...

...doesn't seem like what I was paying for.

Ok, now I'm complaining. 

50% off weekend? 

Don't expect that any time soon really, but yeah knowing valve it will come eventually. 

http://www.l4d.com/blog/post.php?id=3069

The last interview is with Dario Casali, you know, the old q mapper. :) 

yeah that solved the problem! So L4D2 is fun, but the demo seemed a little short to me. 

Thanks for all going and playing this while I'm stuck on a mate's fucking dongle @ 50kpbs because Virgin media are fucking useless cunts despite it being 2009 and well into the era of super-fast IT etc etc it still takes them 2 cunting weeks to get a phoneline installed and a further cunting week to get my fucking broadband set-up. CUNTS. 

You're taking it pretty well, if I were you I'd be raging up! 

There's a patch that removes the awesome in about 24 hours. 

At least you can play it. Haven't tried the demo yet (only just got around to buying Machinarium), but I have a feeling it'll make my PC cough, stutter and finally collapse in a cloud of burning plastic :(