Hey Hannes! Nice to see you still around and making excellent art! CGA has to be the most evil palette around, but you've done some good work with it. Overall, these are some very impressive portraits, but I have a couple of minor crits...
On the first one, I think you could articulate the detail in the hand a little more...kind of vague at the moment, and it's looking almost like he has three fingers. In the second, I'm not quite sure if the light areas in the middle are his eyes, or under-eyes or glasses. The only thing I can see in the last image, is that there is a slight dent in the brim of the man's tophat, right at the front. Other than those very minor things, this is great work!