Just as I mentioned in my previous review, this two part episode is incredible in the way it takes multiple plots and combines them all together into something that drags us even further into the conspiracy.
It's tough to comment on anything new that I haven't mentioned in the previous episode, but I'll just add that the suspense in this episode dwarfed just about everything the show has done before. Whether it was the exchange between Scully and Samantha or the discovery of the alien lab that the clones were running in the women's shelter or the submarine in the Arctic (it's no wonder the image on the front of the Season 2 box set is the submarine with the lights on).
Everything was tied up nice and neat by the time we reach the end, and I wouldn't be surprised if we returned once again to the random monster-of-the-week episodes. But either way, at least we got an incredible batch of episodes that keep us on our toes.