Your work always looks great! Great colours! Your stand-alone sprites are great, but you did a really good job with the background. There are so many different textures!!!
As far as dithering goes, you kept the dithering fields small to minimize noise which is good! Dithering's a good technique to master for blending or textures, but with the range of colours that you usually use, I don't think that it's necessary. Working with restrictive colour limits (3-5 colours) might be a better exercise if you want to work on dithering more!
I would also suggest using more AA, especially in places like the background. Selectively softening and blending edges can add more dimension!

I think it's a great piece. The the background is nice, yeah it probably could look more rugged but mountains are hard in my opinion. The foreground is wonderful, it's detailed, shaded and has depth which is awesome man. And I love the cute little dragon. The scales are very acceptional work my friend. In all I think you did awesome and it turned out to be a wonderful piece.