I don't mean the sky at all, but a type of blue. I'm pointing out that the dark blue ground feels artificial in colour and I suggested more appropiate colours to try out. Sorry, should've referred to that.

Chances are, imgur compressed the image in a JPEG manner by uploading it directly. I can definitely see the artefacts in that pic so there's something not right. Save it on your computer first and imgur likely won't do that again.

As for the tileset, you are limiting the gradient too much. I'm also not sure what the red is really meant to be, and the top of it barely has any contrast. There's also nothing to make it look smooth. Also, the grey ground has what I like to call paper shading/lighting (which is basically when it's not applied like it's a dynamic surface, but rather it's all just applied to the left and right directly). Here's a simple, hasitly done image of what i mean (with limited colours because lazy).



I'll make an edit sometime...if I knew what the red stuff was meant to be. If it's grass then it doesn't feel like it symbolises it very much, perhaps partly because the roots are hard to see. Also if im not lazy, I may fix up the perspective and make a simple template for the rest.