As far as I know, this is the only one that has 
the background...  The reason why there are 
white and black cels in this sequence is simply 
because in the shot, it goes from black to 
white, then pans up the wings until they almost 
shatter into fine feathers flaoting around.  If 
you've never seen Generator Gawl, I would 
definitely recommend it.  Just this short part 
of the opening sequence really got me 
interested, to wonder why they would show the 
main character (and the other two sort of) like 
that...  Really quite artistic  =)

laterz
Rekka