I played the demo and didn't finish it. It was good until you had to stealth your way through a zombie room and the stealth controls/mechanics simply did not work.
I'm going to assume that the demo simply takes place at a part where you should understand certain mechanics that aren't shown/taught in the demo, but judging from first impressions off the demo I am skeptical about all these reviews.
Uncharted 3 got a 10/10, GTA4 got a 10/10, Skyward Sword got a 10/10, none of which deserved such praise, where as Deadly Premonition got a 2/10, which is better than all those games combined. I seriously smell a case of popular developer/popular game = high scores.
But we will see, I'm definitely renting it from Gamefly and excited to play it in whole.