Patxinaki: The balance is okay, since they're moving figures they can be tilted this way or that and still look correct.
Two things I noticed is, with some exceptions, a lack of overlap and no indication of foreshortening.
Introducing overlap is simple on a basic standing figure, if you know the general shapes of the basic anatomical parts: head's an oval, torso's a rectangle, pelvis is a rectangle. It's possible to represent them differently but that's the basic idea. I want to stress that by shape I mean just that, if you wanted you could cut those shapes out of paper then experiment with different poses, don't even need to worry about perspective, and still it's possible to get decent space, foreshortening, and solidity out of it.
Another technique is to use circular cross contours like those found on a cylinder. I noticed that you were dividing the arms and legs with straight lines, but if you divide them with lines of varying amounts of curvature you can indicate different amounts of foreshortening.