Hey Costas!
I think it is a good effort put into this one! The uniform is pretty good, the outlining is really sloppy though, and should be fixed, I mean look at the ribbons and how neat they are.
The skin color have a nice color to it, but I would paint the highlights a little more opaque and clear, that way you really accentate the high spots. Try to make them a little more graduent instead of dark to light so fast.
Don't worry my friend, you are getting better and better and painting larger scales with acrylics takes some getting used to. Just keep at it and you will get there!