Fades
To get that background line to fade with the foreground guy lookig up at the stars you have to actually put everything into one layer. With no symbol instances above other graphics. This makes it hard to change later. So you can keep it like it is until the project is done, then dump the frames in question all down into one layer. You can always save a copy of the original.
Nice style. But as you are no doubt aware your rendering skills could always be improved.