I finally finished the game. My campaign lasted 333 days. All my soldiers were top rank. I had 2 snipers, 2 support, 2 assaults. 2 of 'em had PSI ability. The last stage was very long. I think my final battle was a bit easy:
One big thing that was missing in the game, imho, was free-aiming. I liked being able to shoot out walls in the original game. Then you could also shoot mc'd aliens. All in all, it was a short, but enjoyable game. Time to restore, and finish off some more achievements