Again, one of the things I most like about this series is how they don't hold back. It's a lot of only having 10 episodes a year - I said talked back to my TV, but maybe was the loudest when the "returning in Spring 2014" graphic came up during the credits - but it's also of the show itself having no fear in blowing up their story.
so, after a few episodes of teasing the redemption of a serial killer, Helena utterly snaps one more time and one last time. The Helena as Sarah scene was a bit unfair, with Helena's scars coming into view and the wig becoming very apparently only as soon as the knife was jarred in (plus Helena being able to act like Sarah for even a couple minutes), but one clone playing as the other has been so accepted that I'm willing to let it slide. It was an awesome shock moment, one I completely didn't see coming but made sense in Helena's extreme logic. I don't quite understand how Helena got Amelia into an abandoned warehouse, but it was a great enough place for the final Sarah/Helena meeting, and I liked how London Calling Helena started off the fight with a headbutt.
Helena dying leaves a surprisingly big hole in the series; as much as the Lekee/conspiracy stuff was supposed to be interesting mystery (and still is to a lesser extent), all the tension came in the Helena scenes. It's going to tough to replace that with Rachael Duncan, Dr. Leekie or even Mrs. S, I guess. That last scene was indecisive - Sarah surely thinks Duncan/Leekie have taken Kira and Mrs. S, but Amelia was definitely suggesting there's a lot more to Mrs. S - can't be part of the Dyad or they would've known about Sarah, so some third party? - and I figure we'll find out Mrs. S ran off with Kira before anyone else could get there, and maybe not for all good reasons.
(In the meantime - Sarah and Felix should probably be back under arrest, right? I don't think their lawyer is going to keep them on as clients, and it's not going to get any better when they find "Sarah's DNA" all over two bodies in a basement, including one that looks like here. That's a knot that's going to be tough to untie.)
I really didn't grasp how patents in the Genome made the deals worse, but at least one of the new closing scenes made it clear the Dyad were making promises they had no interest in fulfilling. Alison's instincts were correct in the first place, Donny's been her monitor all along and Leekie's promise to call the monitors off only just got Aynesley killed. I didn't really like that turn of events at all - it feels like it breaks the character. Alison went from the mostly comedy soccer mom doing whatever it takes to keep control of her life to someone just as crazy as Helena, and there's no way to come back from that.
Even *I* know DNA is coded in pairs, like binary numbers, Cosima. Where's my PhD? (The bit where she found out her code number was very well acted.)
The season ended with the clones all breaking down - Sarah mentally, Cosima physically, Alison emotionally - which was a nice theme work. I also appreciated how many things came full circle - Helena playing Sarah in the condo where Sarah was playing Beth in season 1, Alison's willingness to let a death work for her only slightly different than Sarah's, Cosima's blood cough in the last episode just like Katja's in the first. This feels like a series that's been tightly plotted out, and I have a lot of trust that they know the answers to the questions they've left hanging.
Still have a lot of those. We never did find out if Beth knew Sarah was going to be on that train platform. We never found out if every clone having it's own distinct nationality was designed, and why if so. We don't know if it was the different personality traits were engineered, environment, or both (though it now seems more like the second one after what was revealed about the DNA.) And we still don't know how many clones (or proclones) there are out there - they implied Sarah/Cosmia/Alison were the only 3, but maybe the only 3 who've become self aware.
This was all a lot of fun and I can't believe I have to wait 9 months to see another season.
The final scene with Lionel looking into the camera and pretty much saying "you guys getting ready for the super-duper finale?" made me cackle. I think Lionel just didn't care from which reality Clark came.