I would say the only thing that looks a bit wonky to me are the shadows.
The background plate is obviously full sun (very sharp shadows from the little rocks on the ground, and on the face of the big rock), and the dragon himself (herself? itself?) seems in full sun, too (sharp shadows on the face, etc.). All of that looks good. Yet the dragon itself casts very soft shadows underneath on the rocks and ground... as if it were maybe a cloudy or cloudy/bright day...which doesn't seem to quite match the full-sun look of the rest of the scene.
That was the only thing that looked a bit unnatural to me.
Of course I'm being picky and it's infinitely better than anything I could do (that's not my area of expertise at all)....
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