As the first part of a two-episode finale event, it's hard to judge the story on its own merits. There is a lot of setup taking place throughout the episode, all pointing towards an action-packed hour in the true finale. Also, the content and structure of this episode strongly suggests that it was written and paced as a two-hour piece, cut in half for scheduling purposes. At the same time, there are elements that can be discussed that pertain specifically to this episode.
Starting the episode from the perspective of Alt-Fringe was a nice touch. At the onset, it established the personalities of the Fringe Division on that side, how much more advanced they are technologically (in an everyday sense), and how they have been hardened from the constant rifts and incursions into their reality. This was all mentioned before, or predictable based on the technology used on Fringe Prime, but this really drives the point home.
It was such a good example of "show, donât tell" that the scene in Walternate's office was ridiculous in comparison. The exposition was just plain terrible, and it was simply to explain that Walternate has been hiding the truth about the nature of the degradation of Alt-Fringe from the public and most of the first-response operatives.
This may seem like a minor point, but the writers spend a bit of time showing that Walternate is a dastardly villain with a secret agenda. We already know that agenda is the destruction of Fringe Prime, but this makes it clear that the people in his own world are being kept in the dark. This eliminates any pretense that Walternate may be acting out of a sincere desire to do what is best for his reality.
That depiction of Walternate is supported by the apparent plan to use Peter, perhaps due to his time in Fringe Prime, to power a mechanism to achieve the destruction of "our" reality. The implication is that Peter would not survive the process. This all but eliminates the one potential saving grace of Walternate's actions: that he had been seeking to save his son before destroying Fringe Prime. It even appears that Walternate allowed his wife to believe that his decision to bring back Peter was out of love.
Making Walternate and his knowledgeable allies' motivations inherently evil is not nearly as interesting as making them a matter of necessity. Imagine a scenario in which Walternate is portrayed more sympathetically, not unlike the characterization of Ginger Olivia. Ginger Olivia was clearly tough and dedicated, but her motives were justified. Fringe Division in her reality is just trying to save the world; I'm fairly sure the same cannot be said of Walternate, which is unfortunate.
The writers could still have Walternate attempt to convince Peter that his sacrifice is a noble act, and not one taken lightly, but the undertones of Walternate's portrayal already suggests that Peter will be forced into the role if it comes down to it. In fact, it may be that Peter is told the device does something else entirely.
My suspicion is that Peter is playing along to learn as much about Walternate's plans as possible, in the hopes of derailing them and saving Fringe Prime. After all, Peter is highly intelligent, and itâs unlikely that he would miss the purpose (or potential purpose) of the device that Walternate has been building. And I'm still not remotely convinced that Peter actually harbors a desire to help destroy Fringe Prime, or even allow it to happen through inaction.
This episode also sees the return of some previously featured fellow cortexiphan test subjects, revealing that they can use their abilities to "resonate" and cross over into Alt-Fringe, if their energies are properly focused. While it's definitely interesting to see them coming together and using their abilities, both for altruistic and personally satisfying purposes, this does seem like a missed and even mishandled opportunity.
Some things are just better when they are vague and mysteriously threatening. The aftereffects of a pyrotechnic burst around a little girl, for example, are more chilling than someone generating a fireball. It's interesting to see how the abilities of these so-called "warriors" could be used to help as much as to harm, but it just felt like a bit of a waste when their abilities all backfired in Alt-Fringe, turning against them.
All except Olivia, of course, who seemed to be fine. But that brings up another point. Olivia's abilities were supposed to be slowly but surely developed, since she was the most successful test subject of them all. William Bell was awfully proud of her. Yet the writers never really returned to the concept of the multi-staged testing and training scheme introduced in the first season. So exactly what are Olivia's abilities, beyond being a Wrong Universe Detector?
One might also wonder if Ginger Olivia and her lover were part of some kind of cortexiphan experimentation in Alt-Fringe as well. Those tattoos were prominently displayed, which means they refer to something significant. As it feels like this finale is being used to introduce some major players in the Alt-Fringe reality, rather than simply bring them in for a single appearance, this is one mystery that could stand to be left untouched for a while.