My opinion about Studio Pierrot animation still the same, pretty good and solid but too condensed colouring, it's a bit better though.
Now regarding the plot in this episode, I think the pace was a bit too fast, as if they were hurry up to something or to some turn point of the story, maybe because of Korra's impatient and reckless pace, but still a very good episode.
Now characters, Korra, I think she is quite disconcerted with all these events around Unalaq and this Civil War she started, she is so focused to protect or get help in the war on the side of her Southern Tribe to the point she forgets about the Dark Spirits problem, making even more irresponsible and rash decisions and jump to conclusions, enrolling herself in more problems, becoming more indecisive, you can tell she hates being indecisive so instead prefers take action first, she is trying to do her job though in a wrong way and because that brings problems to the relationship with her boyfriend, Mako who also is trying to do his job that comes to a point they break up, Mako is trying to be rational while Korra is being emotional and not trying to be rational (for hating to be indecisive and realization of her lack of experience as the avatar frustrating her), I wasn't surprised they broke up, because I expected in the future they would break up (being fiery characters and one is rational and the other is emotional, sometimes collapses and breaks out), I was surprised by the timing of the break up, I thought it would be later in this Book or in Book 3.
With these recent events, Korra feeling and thinking everything is against her, nothing go on her favour but being consequential from her rash and reckless actions to the point going on a boat by herself (crying from the recent break up with Mako and recent events) and then suddenly being attacked by the twins (Eska still mad but kinda sad at the same time because of her wedding with Bolin) right after both of them (Korra and the twins), attacked by a Dark Spirit and it ends, cliffhanger - very like the end of episode 8 of Book 1.
As for Unalaq, I suspected he said he didn't need her to open the portal to the Spirit World in the North Pole was just a bluff to look like he had the upper hand or he was ahead, it sounded too weird how he didn't need her all of a sudden, since the Avatar is the bridge, it's the only one who can do it, he asked the twins to bring her for this reason.
I say this again, Unalaq is definitely a character that neither black or white, I don't see him as evil but neither good side, he is not doing not for others or for himself (once again not black white), but something else, his objectives looks very invisible and deep, but I have some suspicions what his objectives are and going after them in a malleable way (which I will talk about it later).
Varrick, I can't say much but he's crazy, but there is nice and thoughtful touches in Bolin, he is kinda trying to help Bolin to find answers what he wants to do with his life, I think that's when starts Bolin real growth from now on.
Another light touch, Tenzin is starting bit by bit bonding with his children, episode 4 it was with Ikki, this episode was with Meelo, which means next episode is with Jinora...
Episode 5 to episode 6 to episode 7/8 and 9, there will be a connection between these episodes, specially after this sudden Korra disappearance together with the Dark Spirit, I think Korra will be immediately go to the Spirit World, but in episode 6 there may have an absence of her, while Mako doing his job as the description says he uncovers a conspiracy going on against Future Industries (it may relate with Varrick, don't forget his biography no matter how funny and eccentric he is), it will focus also what's happening Tenzin bonding with Jinora, that's when Jinora spiritual and extremely important role in this Book will finally start take shape, Tenzin will discover his daughter being able to connect with the spirit world, I think he will be quite impressed, now as for the rest...no idea (Unalaq is very hard to read).
Episone 7 and 8, we already know what will be about, at least I think this will be about more about avatar in itself, and to know that where it started the reincarnation of the spirit of avatar which go on and on in different humans beings and how it chooses, I'm sure if Avatar is chosen by seasons pattern, so is something can't be done randomly either, I think this will uncovers some mysteries even confirm some theories I had about the "Avatar Spirit" for a long time before Legend of Korra, that is very complex, we get to know what it means in more detailed way what means the Avatar being the Bridge between the Natural World and the Spirit World.
From looks of the trailers, after Korra learns about the origins of the avatar will have a deep impact on her, I'm sure, if we notice when Korra comes from somewhere of stones shining, she encounters from up with the Fire Sages, I think is when she gets out after learning more about being avatar, the tone she says it and looks at them you can see how deeply she is affected by something and taking more into consideration(once again must be related with backstory of the first Avatar), also will probably take her come to Tenzin of when she admits she needs more than ever Tenzin's guidance in her spirituality as the avatar, that's when relates with the episode 9 "The Guide".
Episode 9-12 will be many times around Korra travels to the Spirit World.