Hi Alberto!
Allow me some considerations here:
next time, to increase the contrast because this is a small figure (1:35), I think you have to add a 5 o´clock shadow in the face area and also a rework in the leathers, K98 pouches etc.
The fieldgrey jacket need the buttons paint with a lighter fieldgrey color to give the 3D effect, and you should be more careful in the jacket outline it seems very harsh.
When my hand was not so steady as it is now,
I used oils (mixture of green and black) because is better to corret.
The scenerie is great with a good house painting and a nice groundwork.
I think you have here a nice miniature, your second it will be better and so on, so paint paint paint.
A big hug to you for your courage posting your work here.
ANYTHING JUST ASK, you are in the right place.
Pedro.