Hey that's much cleaner! Good job! I can't wait to see how you continue to improve. We all can improve if we're being honest with ourselves. 
Hello!
Thank you for this great feedback! I read through all the tips and improved my current work little bit based on what you recommended. I havent done any pixelart in such a long time so it's my comeback challenge/art! :D
Not too bad! There are a few things you might address.
It's quite rough. The lineart is a little messy. Especially your black lines. Take it from someone that uses lineart in almost all their art, it's tough to break away from, but used sparingly it can enhance your art tremendously. Here it looks like you used it randomly to outline rocks and make squiggles in the background. I assume it's a barbed wire fence at the top of the hill. Still, when you can help it, unless you want something to be ambiguous or intriguing, try to make it as clear as possible for the viewer. Don't make them have to guess. Quick squiggles and bulky random shapes usually aren't very pleasant to look at.
Your colors aren't too bad, but you might think about the concept of hue shifting. It can really increase the dynamic pop if an image. When you see an object in real life, it's rarely just one plain color all the way around. Sometimes it will reflect colors from other objects around it. I've seen many artists make the shadows a cooler color and highlights warmer color, but that's not a rule, just something to try.
The biggest things that I can see you should work on are lighting/shadows, form, and color. These things all come with time so don't sweat it! Just keep working at it and keep making progress. You have some really creative ideas! Don't lose that and keep making art you love. 
Thank you for your positivity and encouraging words! People like you are the reason I keep coming back to pixeljoint!