Since you wanted criticism on the art and not the gameplay:
Typical lowest effort possible 'indie' pixel art- nothing stands out, a game like this will need to ride on the gameplay, if no graphical update nor story is intended. There's nothing inherently wrong with each sprite, but the characters blend into the background and everything is overly low visibility. Not sure why there's a coniferous forest on a savannah-colored map, either; you could assume it's dirt, but there's obvious attempt at a full grass texture with the sparse pixel lines. Doesn't really make much sense. If you intended for it to be fall, reflect that in the tree colors. Viroa covered the rest of the issues I noticed outright- and don't be so defensive to criticism.