Cześć! and welcome, nice to see another Pole around here.
Yeah. . . I, too, believe you can do better with the head. There are few little issues that you might want to polish more:
a) the head comes out a bit rough while compared to the neatly-made walkcycle frames (some more aa here and there wouldn't hurt it prolly);
b) the head's off perspective (the background ruins it totally) -- looks like he's leaning to the right (his).
However, I'd say that's better than good as for the first 'serious' attempt. Congrats!