I'm very new to pixel art myself so I might be wrong on a some points but I guess critiquing helps and I can also notice a few things.
The contrast on the cloak is quite low, making it hard to read the shapes and the amount of colours increases while it does not dramatically effect it. The hair also only has one shade so I would add a highlight colour to it and maybe shade his right arm(our left).the body also looks a bit split in the middle although doing it differently could be hard on this low resolution.The arm also looks like it's bending behind but its going in front of the body mostly because the arm has no shadow onto the body.As for the animation,Its quite stiff although I don't have enough knowledge to tell you how to fix it. Here is a quick edit though I may have lost the grim, dark feel of it: