Hi TF,
I have the same problems, I have a 500MP G4, 192MB, Radeon & 9.0.4, and F.A.K.K. is behaving very bad. I have the same problems with hanging when it loads levels, my guess is that there is something in the code that are overwriting stuff now and then. I can somtimes load a level if I just ignore everything else in the current level and just head for the exit, but if I go exploring the level I will surly hang at the next loading...
Also, somtimes I will loose the textures on all other characters and somtimes the sound during the intermissions and when talking to people is gone, restarting the app usually cure this.
But this is the most buggy game I ever have tried, makes Unreal 1.0 feel stabel

I hope they will fix it soon since I accually enjoyed the demo.
Just a question, do You have the Quicktime 5.0 preview installed? (I have... I wonder if...)
Cheers!