Okay I beat the demo on normal.  First thing I immediately felt was this is NOT uncharted with zombies.  Joel controlled and felt like a real human with weight and something that can get tired.  Controls were similar to Gears of War.  Nothing felt awkward or weird.  I didn't find any complaints to be had there.
Graphics.. For me, coming from games on PC spoiled me visually so I wasn't too impressed graphically with the game BUT that's a given when you're used to something else.  I'd say it's on par with UC3 but given the dark place you were in the demo it's hard to gauge how good they really are.  Nothing bothered me.
Sound in this game is amazing.  The ambiance and atmosphere really kicks in full throttle when you're inside the building.  The clickers sound scary and I was always kind of tensed up walking around.
Gameplay is where I felt the game shined imo.  Watching clips of the game does it no justice.  The shyt you see with Joel swinging pipes and stabbing dudes in the neck all smooth like is all controlled by you.  It felt really nice holding square for heavy melee attacks and repeatedly mashing it to see a nice combo.  I liked how you can hold sprint and do a heavy running melee either barehanded or with a pipe.  I got ambushed in the later part of the demo by a lot of those enemies and thought shyt was cool.  Again do NOT go in this thinking you're going to shoot and cover your way through the game.  I died several times on normal.  
Stealth plays a big role.  That listen mode feature I didn't even know it was on.  I didn't even use it nor remembered to use it because I thought I was nathan drake and had to quickly sprint out of the way because it was getting a bit too real.  I can't wait to see what other weapons you find in the game.  Every shot or hit matters.  Again you are NOT going to take cover and aim and pop your way out of the game.
I started the demo over on hard but quit it because i want to play more of the game.  The demo was short but it basically left you wanting more in a good way.  I can't wait for this.