i really love the look of your game! the almost unshaded feel to it is super cool. What would make it look cooler is good color selection. Maybe if you used more exotic colors like in the game hyperlight drifter.
^this is hyper lightdrifter
hex: 00FF7D color for the grass
hex: A35F3F color for the dirt
just my color suggestions
you can do the color edits later but what matters is the gameplay, good luck!