Rei on 18 April 2009
Final Fantasy games are very different from one another. Even if you liked one it doesnt mean you'll like any other. So my advise to you is do not listen to any suggestions like "play this one FF, it's the best" if you personally dont like how the named game looks.
If you like how XIII looks and plays then just wait for it, you dont need to play any other game in the series to understand it.
