I have played several Ninja Gaiden games from beginning to end (including the most recent Ninja Gaiden 2) and I thought the Ninja Blade demo was superior to anything I had ever seen in a Ninja Gaiden game. I thought the action was more intense, the battle system was more fun, and the graphics were definitely in a different league. Yes, it was a 10 minute demo, so maybe the rest of the game sucks, but I can't imagine that being the case.
I personally tend to agree with IGN's reviews most of the time, so I will probably wait for their verdict before buying the game......but I really wanted this title to be an unquestionable day 1 purchase. Now I'm starting to doubt my first impressions about the game. Ah well, maybe I'll throw caution to the wind and buy it anyway.