In the first picture (Artist Nesterov Mikhail) I liked a rhythm and balance.
In the second picture (Artist Michelangelo Merisi da Caravaggio) I liked the focus the human face and economy painting.
Time spent an hour on each.
These are coming along really well. You are very talented. moving forward, please pay very very close attention to your use of values. You are getting your levels off just a little bit, and are sometimes missing your lightest lights. I would suggest going back through your images and spending 5 minutes each on adjusting the levels and value range. It is so close. I just want to push you to be perfect on value control as it will pay off on all your other paintings you do from here on out.