You did really well with this entry! That being said, I had some constructive criticism I wanted to share.

I am not exactly sure what is going on with the reflections in the windows, however. I think it would have been fine without them because whatever is going on is distracting from the focus aka Flash.

Speaking of focus, while I like the idea of his thumb photo bombing the selfie, if you blurred it a bit and adjusted the shadow on the thumb pad, I think it would help keep the focus on Flash. (press your thumb to a glass cup to see what I am talking about.)

Lastly, also taking the base of the building out of focus would help keep the eyes on him. Phone cameras rarely seem to keep anything other than the focus of the image sharp.

This is my first review on here and I hope it helps. I really liked this concept!