Had a bash at the multiplayer demo for the PC, few things i noticed.
Graphics : Much the same as the original, i didnt expect more since this was developed for consoles too, with that said the orignal Crysis is still one of the best looking games around and this is no exception, it does look fantastic. Runs fine on my old computer too, i'd say requirements will match that of the original Crysis.
Gameplay : Some new modes, energy works different, will take time to get used to. There seems to be some kind of aim assist, you would normally see on consoles but its on the pc too, and available to use in MP matches, i'm not a big fan, helps a little with the lag i guess.
Online play : The servers i was playing were too laggy, i never got on well with online shooters when you shoot someone 10times in the head and they survive because of the lag, but this is quite bad, its only a demo so i expect it will improve but i counted a good 10 kills per match that ammounted to nothing over the lag.
Balance : Again, its only a demo but the balance is way off, the guys with the snipers and shotguns were dominating, the assault rifle is not the most accurate, sniper rifle seems overly accurate and powerful, the nano strength jump thing has a massive range and is instant kill, a bit over the top. Stealth mode seems glitchy, i saw some guy stay in stealth while he was pumping pistol rounds into me, again just a demo bug (ie i didnt see him shooting me, though he was standing directly infront of me, only saw it in the kill replay)
Personally, if i want online play i'l probably stick with battlefield, but i'd imagine the single player, much like the original is going to be action packed with a storyline and amazing visuals, which is what i'm looking forward to more.