I was going to do exactly what you did, and yes, I noticed a good difference in colors. Thank you so much for this, seriously. It's this kind of criticism that makes me evolve. Thanks bro! 

Adding barely-visible shadows is the opposite of minimalism. In HLD's character sprites, they stick to a small number of highly distinct colours and don't have any barely-visible shadows because small areas of low-contrast colours are so hard to see that they may as well not be there. HLD has very visible shadows when there's room for them, and no shadows when there isn't, they instead rely on colouring entire limbs/sections a solid colour to convey the design.

In your fox, rather than using minimal shadows just to convey the distinct parts of the body, you added a bunch of shading to everything, even though there isn't room for that shading to read well.

Here's an edit of the fox that reduces the number of colours on it from 15 to 5 (and I also made the oranges a little more saturated so they stand out better from the sky). Can you find the "missing" colours without zooming in? (Zooming in makes the small areas of colour become large, which allows them to stand out a little better.) I suspect even you, the artist, will have a hard time without zooming in because the colours I removed make so little difference in the original.

Thank you very much for your opinion, but I wanted to try to leave minimalist, if you go to see the art of the Momodora you will see that the colors are solid, without much contrast of light and shadow, anyway, I will darken the colors a little of the fox. Another thing is that this was just a test of the animation, I wanted to see how she would run and jump because I'm still learning to animate. I made another art with a background, but I just did not publish here because they are just color tests and drawing. That's it, thanks! 

I think it could really use a bit more negative space (just more sky) at the top. The fox is the focus of the image, but it's nearly hitting the top edge. Give the poor foxie some breathing room!

The fox doesn't stand out very well from the background because the values on it are very similar to those of the background. Making the sky lighter and the fox a little darker should help. If you don't want to change the values of the sky or the fox, try maing the orange on the fox more saturated so that it stands out a little more from the blue.

In addition, the shading on the fox is barely visible. Try increasing the contrast between the shadows and lights.