oh! I understand now, thanks a lot Jalonso for the time & advice, I am going to try this

"The goal should ideally be working the colors so they look good but also balance their job in maintaining line balance."

Here I meant that if the yellow used to line the ground behind the wolf is too strong then change that color to a better suited shade (hue, luminosity, value, etc.) or use another color (maybe the light green) in your palette until the line weights visually looks balanced.

 Thanks a lot Jalonso for the advice, I am going to try this ! : ) 

"If the jaggy pixelly look is the idea and what you wanted" no It's not, I have to fix that

 "The goal should ideally be working the colors so the look good but also balance their job in maintaining line balance." didn't get the meaning of this part of your message ( maybe because of my english )

Woooa! Now I can appreciate and rate this piece. Colors are awesome.

4 colors? very nice

Some images really ask to be smoothed a little and this is one of those. Notice the clouds that are in the far BG have a smoother apperance than do items near the viewer. In pixelart this exxagerates the jaggies and kinda forces AA on you. If the jaggy pixelly look is the idea and what you wanted then the clouds should match too. You have tiny bits of dithering that don't add much and by their isolated usage stand out as bad design choices.

You have the right amount of colors to beautifully AA and dither this piece into a knock out :/

One other thing that happens with pixelart is that color choices matter a lot. Notice how much thinner the lines of the wolf are as opposed to the lines of the ground just behing it in yellow. This is where palette optimizing and modification comes in. The goal should ideally be working the colors so the look good but also balance their job in maintaining line balance. Tip: this is great to know for when you want to create the illusion of 1.5 pixels lines.

 thanks, I changed to 1x size :)

 okey I changed to X1 and some highlights

The pre zoomed just kills the image and just highlights some of the messy areas :/

Not bad. I like the color and the style. But please use 1X size.