To clarify, I pretty much only watched this because I'm a big fan of IU.

Love set- the plot was rather meh, and tbh IU's foil feels like a far more capable actor. The entire episode has a sexual element to it though, which I suppose is pleasing to the eyes for some.

Collector - Beautiful acting with IU as a "fox". with probably the best acting in the series. I concur with the other reviews that it's a reflection of women in society, and perhaps more personally to IU as an idol (who takes love, but can't really ever give it in a meaningful way).

Kiss burn- i didn't quite get this episode, and IU with a cigarette looks like a gaff (though it might be intended that way.)

Walking at night - This feels like arthouse cinema, shot in an nostalgic noir style. It definitely feels more intimate of the four, and the director has made some excellent choices in the lighting, sound (e.g. silence, with cricketing in the summer) and location which really grounded me. The shots are simple, but perfectly done. The acting was also great from both parties, though with expressions somewhat suppressed to feel more realistic. As you can probably tell, this is my favourite episode by far, and is a must-watch.

I've rated the show as 9/10, reasoning being rating Collector 8/10 and Walking at night 10/10. Love set & Kiss burn are skippable in my opinion, but the other two are a must watch if you like to see IU's potential in more artistic setting (with walking at night just being an amazing piece of cinematography overall).