You need to play with the lighting and colouring of this image a bit more author. The stone arch looks too green and saturated against the rest of the image.
Maybe bring the colours of the background out more, or add a little contrast to it even
Goodluck.

For me...and only speaking for me...the lion head is a tad distracting. Doesn't seem to blend in enough with the "gateway". Also, watch your masking. There are a couple of places that could be cleaned up a little. Other than that, good concept.

Love what you are trying to do author! IMO you need to play with the perspectives of the various layers so they blend a little better....Best of Luck

I like your idea.... good luck...!