As we mentioned in our "Mode of Production" analysis, we're still pretty much aligned with Harry's narrative perspective, which means that the storylines are simple: We're on Harry's journey, traveling with him, seeing what he sees…you get the picture.
However, there's one little interruption to that linear path, and it comes via Snape. Right before Snape dies, he gives Harry a memory to "watch" in Dumbledore's Pensieve. Through that flashback, we learn that Snape is loyal and has been protecting Harry all along.
Also—less happily—we learn what Harry's next step must be: sacrificing himself to Voldemort.
It's a brief interruption of the main narrative, but that memory definitely shakes things up big time for Harry and his friends.