For a series that has a good soundtrack, the director's placement of that soundtrack has made me feel some disillusionment with his slapdash use of it.
One musical interlude cuts off another when the topic of Nen is raised, undermining the elegance of the scene. One jaunty bit of music invades one of Wing's explanatory scenes, hurting the gravity and attention his words demand. Familiar chords reappear in every episode, which grates when their use is superfluous, or even routine--as I feel it is here, such as where Gon and Killua leave Wing's place to talk about the threat. Most apparent is that it is only rarely that the storyboard will move in tandem with the music; the music comes across in some moments like it is but an afterthought. It is on that last point that I would dwell most: Hirano's soundtrack is beginning to enjoy the nuance it once lacked, but I'm not feeling the same sensitivity from the director. I don't want to resort to hyperbole, but this reminds me of FUNi's Dragonball Z dub where the appearance of a given character would often summon that character's theme tune when another track was only half the way through--such as the aforementioned Nen scene--and the scene feels messy and even irritating as a result.
I am no greater advocate of any adaptation or form of HUNTERxHUNTER than the other, but as far as direction is concerned, I am not getting on with this one musically. Listening to those previews for the second soundtrack the other day makes me really happy--but that faith wavers with every passing episode when I see just how untidy the music placement can be. I recognise that any endeavour to adhere strictly to the panels of the manga is going to have repercussions for how creative you can be on the screen when it comes to length of manga panels, etc., but that should stipulate either: a different form of soundtrack; or the requisite sensitivity or flexibility when dealing with one as melodramatic as Hirano's--sensitivity that is needed to handle something so bombastic believably. For Koujina, he could afford to take a page out of Hirano's book. Whereas the former is willing to breathe some of his own creative daring into the series, I do feel the latter sometimes tends towards treating the manga as a straitjacket--something that I feel is suggested through music placement that is the victim of a storyboard that can't always use it.
I don't feel total antipathy for this episode. Killua's voice actress is coming along. Killua's design is nicely modelled for his darkly moments. There is some willingness to take creative liberties with the source material, such as what clothing Killua wears, his birthday spiel, plus the cutting of the dialogue of the chaps he was talking to--and some of these liberties reveal some recognition of how best to read the underlying mood of the scene, rather than belittle it with the full brunt of what's in the manga; but if those liberties are possible in the first place, I'd prefer to see them used to better employ the soundtrack. Lastly: when the director's hit-and-miss approach to the interplay between the soundtrack and storyboard actually hits--when Killua is told about Gon's match, for example--the moment is delicious.
These traits do not neutralise my general mood of discontent as far as overall directorial sensitivity is concerned, but I'd like to say they give reason to hope. But I don't want to have to keep saying that after every episode.
End thoughts and opinions.
I like how no background music played during the Killua/Sadasso scene, It just made the scene even more chilling hearing Killua's threat. 
