why is that i don't really see a difference other than a random star in the right side of the first one? <_<
also, you should have tried to blend the lightning on both because its visible where the render ends...
well, you can use the blur tool...
and the chalk brush... just a few strokes on the ends of the chains and the lightning bolts, so the end of the render doesn't look that obvious...
The first one has a little more contrast I think.
use a 65-100 pxl soft brush to erase the edges to blend with the bg.