All in all, this episode was something of a let-down after the previous two. That's not to say it's BAD, but definately not as good as Truth or Hard Salami.
Bryce's return answered a LOT of questions, and it's nice to see my own predictions coming true. Ultimately, Nemesis will generate a LOT of ripples that will shape the end of the season, and possibly the series itself as we're introduced to the sinister Fulcrum. Chuck and Bryce also somewhat resolve their differences, and I think there's a measure of pride Bryce has for Chuck's ability to so effectively integrate the Intersect data.
Also enjoyable was the continuing development of Morgan and Anna, and the meeting of Anna and Ellie, who is unfortunately clueless about Anna's jealous behavior during Thanksgiving (this seemed somewhat out of character, though, as Ellie seemed to be aware of Morgan's unreturned feelings in previous episodes).
However the centerpiece of Nemesis, as well as Truth and Hard Salami, is Sarah. Sarah already suffered severely emotionally after Bryce's apparent betrayal and death in Pilot, and Nemesis only advances this, as she's caught between her existing feelings for Bryce, and her growing feelings for Chuck. This is most poignant in the final scene of the episode where she's forced into chosing between the two (a choice which is yet to be resovled).
As always, the writing and acting were superb. Casey gets to kick some butt, and we're finally introduced to why Sarah and Bryce were so effective as a team. We're also shown a little more of just how in-sync Bryce and Chuck can be as well (perhaps foreshadowing for future episodes?) There are still a few unanswered questions, which that may be part of why the episode left me feeling a little unsatisfied. The promo seemed to indicate there would be a lot of resolution, however much of this may be waiting until next episode. There was also some opportunity to take advantage of a real dramatic turn that was resolved with a twist that's really become rather cliché.
All-in-all it was solid, and even the poorest Chuck is better than about 99% of what else is on TV. I just wish I wasn't left feeling so hungry.