The 40th Day demo takes place in Shanghai were some sort of military attack is happening to it.  Their are certain key features introduced in this game that are actually pretty cool. 
 
Morality System:
 
Their are several opportunities were you have the option of taking enemies hostage. One instance was the game allowing me to rescue civilians hostages by systematically attacking the enemy. Or you could just go in guns blazing and have the enemy kill off the hostages. Also there was a point that the game allowed me to choose to betray one of my comrades. I killed his ass for the money, but maybe if I didn't he would've stayed with us through the level making it easier?  BUT this is where communication is key! Both players have a choice, but the game will go with whomever chooses first. So it emphasizes talking the choice over with your partner.
 
GPS:
 
40th Day has a "where the fuck am I going" button reminiscent of Dead Space. Very handy, and it allows me to see exactly what my partner sees on the top right of my screen.
 
Aggro:
 
While it was present in the original game, the sequel makes the WoW-like system more imperative to survival. Most combat areas were designed to have one guy take the high ground while the other makes the enemies all sorts of pissed off on the low ground. Thus making it easier for the dude upstairs to snipe off distracted foes. 
 
I totally recommend playing with a friend for the gameplay mechanics to shine. Otherwise, it's just a non-descript third person shooter with some cool weapon upgrades. So I guess your enjoyment on this game is dependent on you being able to find a friend to truck through the entire game with you. The only thing I'm kinda bummed out about is the game kind of taking itself too seriously. Of course it's only a demo, but I saw no fist-bumps or anything of that nature. Just a lot of Sam or Rios saying "Get behind me!"
 
If you guys need someone to get through the demo with, feel free to hit me up.

YA just hope the rest of the game is good. And i already got my buddy enlisted for when this game comes out.
FIRST DAY RUN!

" YA just hope the rest of the game is good. And i already got my buddy enlisted for when this game comes out. FIRST DAY RUN! "

I cant wait to play the demo, I downloaded it yesterday but since its co-op only and I have my best friend coming round tommorow im keeping the demo to play through with him. I loaded it up with my second controller for a minute or two (mostly because I was dissapointed in no SP mode in the demo) and the shooting feels so much better than the original, true there are many downsides like the really noticable texture pop-in and generally low quality graphics (well thats a bit harsh, they are perfectly adequate). The weapon customisation menu's make me hopeful because i love the choice of diffrent parts of weapons. Cant wait for a proper playthrough and depending on how my buddy likes it then I may get it day 1 to play through with him.

Anybody have any problems with randomly dying? It seems like sometimes enemies just kinda kill you without the game giving a good indication on what's going on.

I thought the game looked ugly. The graphics don´t look up to par with the rest of the AAA titles that came out this year. And the gameplay was aweful. I actually had high hopes for this one :(, too bad.

You can actually get Salem and Rios to do a rock paper scissors game going (for moments like who's going to be bait haha) , but unfortunately my buddy and I did it on accident so I still don't know how to trigger it.  If you press A next to your buddy you give him a compliment (there was a chest bump and a handshake, I hope there's more!) and B to shove him.  This was all split-screen btw.  
 
The customization where you can just mix and match anything  was kinda weird at first (a G36 barrel on an AK wtf?) and it came to the point  where you really were making your gun, making it no longer a variant of existing guns (which is cool, not so much if you a "gun purist" or w/e I suppose.)  With that said I just wish you can name your gun because the G36c I put together was no longer a G36c haha.
 
I haven't experience any problems with randomly dying. 
 
Um, the shotgun is fun haha.  And I guess SMGs are no longer secondary weapons. :-/ 

To be honest, i thought the demo was 10x worse than the first game. I'm not really sure why, but it just had a way different feel from the first. Also the fact that fucking Nolan North is the voice of one of the main guys drives me crazy. People need to stop resorting to hiring him just because they're to lazy to go out and actually look for a guy. "Hey that guy's in that Uncharted game and he's supposed to be really good! let's get him!!!"

I played the demo on the PS3 and I have to tell you that the demo, by itself, is a hella lot better than the first game. There's more stuff to do in terms of weapon customization and the overall gameplay experience was more enjoyable. I even went out and pre-ordered the game at my local game store to find that they'll knock $10 off of the retail purchase, which perked my interest, along with giving away a new game mode. I understand that alot of people aren't excited for the Extraction mode, but how I see it is free is free. 
 
The demo didn't go without any problems, however. The voice chat in online co-op play was very choppy and garbled at times. I'm not sure what the 360 version was like, but as for the PS3, I hope it'll be cleaned up for release.