I think I’m almost done! I went back to the main story, and found Darko Brevic – who I decided not to kill. I don’t know if that was the right decision or not, but since I’ve saved everyone I could so far, and Roman was quite insistent I spare him, I thought it best.
And then I attempted what I assume is the final mission. I was given the choice of working with Dimitri, or killing him. I chose to work with him, but as expected, he double-crossed me. And I died trying to finish the mission. Pff.