pixel art critique wanted!

hi guys. i've been practicing pixel art. i'm trying to get better at shading, and i found some tutorial on deviantart that i followed for it. i was really pleased with the result at first but now i look at it and realize it looks really off in some way that i can't describe.

could i get some honest critique on this please? i want to improve!

obnoxious colors are to show the shading heh

I personally like it a lot!
I'd say the only way it really looks "off" is just that it might look a bit too stiff? I'm not an expert on explaining anything (I'm a crappy teacher), but I'm guessing it's just mostly with the tail and back just looking a bit like stone and less like a moving horse maybe

What jumps out at me, is the odd shaped butt. It's not near as round as it should be. And the tail should be out flowing behind the horse. It also feels like the body is to big for the head and legs. Other than those few things, it looks pretty dern good!

My biggest tip to you is to use solid colours when creating the base. The moment you add opacity into the mix, it's no longer pixel art and is actually just a variant of digital painting. If you switch to shading with solid colours and not blending, you'll immediately notice a difference in the look and feel of your pixel art; simply because it's true to the style. I'd experiment with adding more flowing lines to the mane and tail if you want a more dynamic look. Other than that, it looks great- you're definitely making progress!