One of the things I look for in shows is continuity. You don't necessarily need one goal or a specific arc or anything like that, but I like to know that episodes don't exist in a void.
The continuity in this episode is great. The references to past episodes don't feel forced from either side. I didn't groan when they were brought up here, and I didn't look back and say "Oh, that's why that happened." It's not exactly retconning or foreshadowing. Just a few convenient circumstances.
The only real negative point I have... might be fixed with some more continuity. The ending is sort of ambiguous, and that isn't always a bad thing, but in this case it feels like ambiguity for ambiguity's sake, not because it benefits the story. I'm not entirely convinced they know what they're doing with the foreshadowing in the final scene, and (unlike continuity), you should definitely know what you're doing with foreshadowing. Maybe they do, and in a future episode I'll have my "That's why that happened" moment and it'll be completely satisfying in every way, but I've been burned by this sort of thing before so I'm not naturally optimistic.
Aside from that, though, it's a great episode. It doesn't get as heavy as the teaser made me think it would.