I hate to say it, but as a long time fan of Fringe, I felt that this episode was a bit of a letdown.
My main criticisms? First off, the whole Robert David Jones arc. For almost an entire season now, we've had RDJ portrayed as the main villain, using a variety of henchmen and minions to carry out his deeds. And all of a sudden, in the course of one episode, it's revealed to us that William Bell is actually the mastermind and RDJ is nothing more than hired help? Not only that, but RDJ then decides that he's going to physically attack Peter Bishop - something which he could easily have relegated to a henchman, which has been his usual approach in the past.
I dunno, the whole series of events leading up to RDJ dying just felt quite forced and out of sorts, like the writers had to find a way to get rid of RDJ and didn't mind having the character decide to get his own hands dirty, which is something he hasn't really done in the past.
And on that note, the RDJ/Peter fight? We've gone from Olivia being barely able to make lights blink, to being able to physically manipulate another human being. Does no-one else find that a bit far-fetched?
I also felt Walter and Astrid's behaviour to be out of character. Astrid has typically been depicted as the number cruncher on Fringe, but in this episode, when surrounded by armed villains, she suddenly decides it's time to employ some kung-fu? And not only that, but all the villains involved must be suffering from extremely poor eyesight considering that they were firing multiple rounds at Astrid and Walter (both of whom were unable to run at any great speed) before any of them landed a shot successfully.
I love Fringe, but with this episode it really felt that the writers were suddenly tying up loose ends with lazy writing, and forcing certain situations. I hope the second part of the finale doesn't suffer the same flaws.