Well, from what I heard, while it didn\'t have magic, the theme of life and death, Cid, and an appearance of Chicobo (in a poster I think) are connected to the games (which BTW, none of the games really connect with each other in the first place except for the things I\'ve listed). Now, you may not haven\'t chosen these things if you made the FF movie, but they are the themes that connect the movie to the games.
Now, why did it fail. This is all from what I heard since I haven\'t seen the movie myself. It was hyped to be most realistic CGI movie (which it is), the problem, its still CGI. So, how can you take the charecter\'s seriously if the "actors" don\'t look quite right (afterall, unlike Shrek or Toy Story, FF: TSW is trying to be more then a simple animated movie [in Shrek, they even had to tone down the detail in Princess Fiona to fit with the rest of the movie]). Also, the acting itself. Someone mentioned the voice acting didn\'t look right, that didn\'t help people take them seriously either. From the movie critics (and to some that saw the movie), right when the movie got "emotional", its also where it failed. Also, the somewhat weak convuluted story. The pace didn\'t excite some people. Heard people were even sleeping during the movie.
Also, adult animation, just doesn\'t do well here in the states (maybe in VHS and DVD sales, buts thats about it) primarily thanks to Disney and its nearly monopoly in animated movies (until Dreamworks Shrek, maybe even as far back as Antz and Prince of Egypt, the idea, if it isn\'t Disney, then it probably isn\'t good). So, until Squaresoft or another company (even Disney to an extent now, Atlantis for them could be a stepping stone to "grow" up animation) changes that mentality, adult animation will have a hard time taking a hold in the US market. No matter how realistic the animation is.
While I had high hopes for this movie to succeed, all well, hope it does well in Japan, Europe, and on DVD (which I will probably get). Still, this isn\'t a one time thing for Square. Heard they are already working on future FF movies, and the digital actors career have just begun. So to speak.