This demo is awesome. The gameplay is excellent!! The demo was of good length as well. I pretty much only went with regular combat, so I could go through it again more blazing, more stealth, or more fists.
I think this game will be great, and whether or not the MP is doesn't matter much (Far Cry MP was well, no one played it) cause it is just an amazing SP game anyway. Though I won't be purchasing it till approx next summer when I should be graduated, working, and have a new rig.
Cause damn... 1024x768, all details low (auto detected too) and I played for 5-10 minutes, and it ran pretty good. So I put Textures, Objects, and Shaders to medium and continue playing. Ran good for part of the time, but quite a few areas it got very noticeably choppy.. downright bad in some places. So if I play through again, it'll have to be 1024x768 all low details for sure.
You'd think my Opty @ 2.7ghz, 2GB ram, 7800GT OC would do a little better, but no. I wonder how they released gameplay videos and playtested early alpha builds of this game in say 2005 or 2006 when there was not the hardware there is today (though 8800GTS has been out almost a year now) at all, cause damn is this game a hog.
So to sum it up, the demo is awesome, and this game is probably gonna be phenomenal.
Still, I think the devs could optimize more and tweak the game more, say spend another 6 months doing so. From the MP beta, sounds like they should. I think EA is pushing them to release. Honestly, I don't see how much you can accomplish in the next couple of weeks. There is so many damn good games now... it's very crowded market (and I'd guess the holiday season is enticing for sales), but I think say a Spring 2008 release would be better as it wouldn't be so crowded with other games and they'd have more time to polish it.