This is a very powerful, very beautiful piece.
The concept behind it holds great impact. Sunsets and sunrises with clouds seem to be entering the realm of the cliche these days with a lot of photographers, same old shot of these. But with this, you've taken something universal (the sky) and put a whole different spin on it.
The originality on this is superb. It's definitely a very cool effect employed, scrolling down and "transitioning from day to dusk to night to dawn.
This is definitely something new in terms of photomanipulation, and if those clouds & birds are the products of brushes, great job, they look very realistic.
Great technique, wonderful originality, powerful impact!