I played the Demo last night and I thought it had the makings for a pretty decent story. Loved how the aliens were killing people with those machines and hearing the screams in the background. portals were definetly wierd and first I've seen portals like these, where you can run around a box and see nothing, but when you look into or run into the box, your in a whole new area. Running around upside down, and seeing other people running around defying gravity was an interesting concept. Personally, I can't wait to rent this game, I'd love to see where this story leads.
As far as people having framerate issues on larger tv's, I don't see it. I have a 61" DLP and mine operated smoothly, no jerkiness and no jumping around. You guys might want to see if your tv's arn't up to par, all of those "Bargin" HDTV's arn't always what they're cracked up to be. I thought I heard somewhere that LCD's are succeptible to framerate problems, I could be wrong though.
Personally I think people need to stop picking apart every little bad part of a game. I'd rather see the graphics get a little weak in trade off for a game with quality play control and most importantly, a good story to follow. There just arn't enough games anymore that follow a decent story line.