Overall a good episode, although I wouldn't say it was great. I will say, Fringe always seems to knock it out of the park with the child actors they get.
I liked Lee's quipping at the end; it reinforced the idea that just like Olivia/Fauxlivia and Walter/Walternate are similar but different, both Lincolns are also similar but different.
That last scene with Walter and Olivia was amazing.
Nice of them to remember Nina/MD exists.
Otherwise, the episode felt designed to bring the audience up to speed on the history. I think all the regular viewers already figured that Peter drowned in the lake and wasn't saved. Unlike last week, which set things up thematically, this week was more of a simple plot set-up. Hopefully next week there will be a little more movement.