For what it's worth, I'm sure the season finale next week will be a lot more action packed, but the first part didn't do much for me. Granted, it was a setup episode, but I expected more. Other than the cool things we saw from alternate universe, which were just enough to amuse me, the episode was severely lacking in plot until the end.
The episode begins in the alternate universe with the Fringe division scrambling to quarantine something. Then we see the reason why. Olivia, Walter, and others are in the alternate universe, indicating that by the end of the episode, they'll have crossed over. After an awesome red version of the credits, the show goes to 36 hours earlier. The build up to the crossover is an uninteresting gathering of former Cortexiphan kids who can control their powers. Once they go to the other side, the Fringe division pounces on them at the predetermined meeting place with William Bell. The two Cortexiphan people die, Walter is shot, and Olivia runs off. The episode ends with Olivia staring at Olivialternate (yes, that's my word) before William Bell comes up to her. I don't trust him, but Olivia seems to trust him, which I'm guessing stems for the childhood experiments.
Peter spends the episode with his birth mother, not necessarily his real mother. It's a odd situation where they are kind of the same people, but not really. Peter isn't quite sure where he fits in or how to deal with years of separation.
The Supernatural season finale had about a minute of action total and kept me entranced the entire hour. A big difference between the two is that Fringe relies on fast pacing and action to get something dramatic to happen and the slower, introspective scenes are hit or miss depending on the characters. Supernatural, on the other hand, can go for huge lengths of time with a slow paced episode due to the complexities of all the characters that Fringe hasn't reached yet.
So what's the machine? It sure doesn't look safe.
Score: 8.8/10