I think the environment is a bit too busy/noisy, it kind of has that old point and click style which everything looks "dirty". It might be what you're going for but I have a few suggestions.
tiles: clearly you're working with the whole tile there, you might want to give yourself a bit more breathing space to the platform for the character looks more interesting visually.
atmospheric perspective: you were almost there on the trees but you need to work on your mountain range, give it a color to blend a little better with the sky.
shading: the clouds are ok(you can add an extra color for shading tho) but the mountains could have a shape better defined. this also goes together with the trees, the ones in the back could be shaded with more broad shapes.