I'm not sure why you saved in JPEG in the first place. (sure it's a png now but I can see the compression artefacts). I'll take it as a mistake.

I would maybe say it looks flat but then again it's a blade tileset, the recent ones usually look like that way.

I'd also go for a more sky blue (or you can check out ice blue). Or a de-saturated brown since that's what frozen soil usually looks like.

Also, you might want to make the shading of the snow a bit darker for more contrast. It's not very noticeable. Then again it's a JPEG which isn't a good way to judge tilesets on.