this shouldn't be in the challenge section, please fix it.
The form doesn't read well. Which arm is on which side? Is the leg we see in front of the arm or behind it? These things should be immediately clear for a solid "read", but they're not. This is because you have lots of detail-shadows everywhere, but your form-shadows aren't very clear, and have the same intensity as the usually-weaker detail shadows. When you draw, whether it's pixel art or not, it's very helpful to start with the important, overall forms, ignoring the details, then add in the details, making sure that the details do not make the overall forms unreadable. It can help to only suggest certain details without drawing them out in full, to keep the focus where it's important, and to keep the overall read easy.
I highly recommend reading this tutorial. It's not about pixel art specifically, but almost everything in it applies to pixel art as well.
You have stolen this from heartbeast you just recolord it!