Spoilers lurk below!!!
WELL. I had some trepidation heading into this episode, but over all, I think it did a great job of answering the most important questions of the season, tying up some storylines and starting others... definitely a better constructed plot arc than last season!
For one, I was not expecting the use of the lake. It's great writing, but I'm not used to OUAT being so good at set-up. It was a perfect way to use two portal instruments that were otherwise useless - the powder and the bean. And obviously it was very well foreshadowed.
It was really nice to get some more flashbacks. We saw clearly how Hook and Cora began their partnership, and surprisingly Regina has a part in that history, as does Belle! It'll be interesting to see how those two women react when Hook shows up in Storybrooke.
Speaking of Regina, she's really starting to grow on me as a character I genuinely like. The more we see of her past, and the more we see of how genuinely she is trying to reform, the more hope I have. This episode was obviously a pivotal place for her, where she finally put Henry's desires over her own feelings.
While we got only glimpses of Aurora and Mulan, I felt their lines were handled more deftly and they were better directed. Mulan actually showed some emotion, and Aurora is positively adorable! I'm looking forwards to seeing them in their quest for Phillip, who hopefully is not lost forever!
But by far the best part of the episode was getting to see Emma and Snow be badass. Snow is an absolutely lethal fighter, and Emma, despite her lack of formal training, manages to hold her own, and even defeat Hook - way to go girl! Who else thought that Cora was really going to kill Snow? And then who thought - for the briefest of moments, that Emma was going to die? I couldn't imagine how they were going to write their way out of it.
But now... now we know that Emma being the "savior" and being the "product of true love" is more than just ending the curse. She's got enough magic in her to instinctively force back Cora, who is arguably the most powerful magic-user in the series (even Rumple is afraid of her). It'll be really interesting to see this develop over the second half of the season, which will probably return to the Storybrooke/flashback format of season 1, now that Cora and Hook are sailing into town... it remains to be seen how Aurora and Mulan's thread will be integrated into all this, but hopefully we'll get to see more of their backstories as well!