This has got to be one of the most peculiar J-Drama I've seen in awhile; It doesn't seem traditionally structured like a normal 4ep drama would be (eg. Friends 2002) but it also isn't avant garde enough for it to get a pass, it just seems like a indie film project that was for some reason split up into 4 episodes instead of just a movie.
The plot itself seems strange. Because I am no where near fluent in Japanese, the more minor nuances of the story were more or less missed at first, but I managed to somewhat get it in the end: ML suspects his girlfriend of cheating, and in typical liberal arts student fashion, he begins something unexpected in response, a documentary of the timeline. Despite it being only 4 episodes long, 23 minutes each, there is a lot of jumping back to the past when they first met and present day, though from all I could tell, most of the past is just his good memories and completely irrelevant to the story (kinda annoying when they could take up 1/3rd+ of the episode). Characters were written in attempt to be deep/thought provoking I feel, but failed. FL just seems manipulative and ML a naive pushover (which was practically pointed out by the tritagonist in ep4).
Technical aspects were good, think I'm gonna stop pointing out how 'good' newer J-Drama are at lighting and all that since that seems uniform in all of them.
Acting I personally think was alright, seemed again like an amateur film project so picking actresses and actors with little experience fit it (not saying they were bad, they all did very well)

Overall I recommend this to people doing Japanese immersion, otherwise don't bother