Personally, I think it's all of those things. One Room more than any show depends on your mindset. If you want to live the part of this unseen first person and watch the bonds of the fake-you grow with three girls I think One Room is good for that. If you don't want to you'll find some disconnect between it and yourself creating some sort of weird feeling. To make it even more polarizing the camera shows you all sorts of fanservice of the girls over the small time that it has. That does sort of disconnect from the first person view but I understand why they put it in. It also doesn't help that due to this sort of action sometimes the character whose eyes we are in does things that the viewer may not agree with or do themselves. There is a reason why characters that the viewer is supposed to self-insert into are usually silent and don't respond, it's to avoid disconnects like this.
One Room actually does a lot right. The characters are the main point of the story, and the characters are well written. Despite only seeing them a bit they do have more depth to them than one would expect. They may fall into the general lines of tropes but they don't stay in there so rigidly as to be noticeable or annoying. For an anime that only has four episodes per person and three minutes per episode, I feel like the treatment of the girls is pretty good.
Furthermore, the conclusions are pleasant. Since this is basically like a dating sim it is important that these conclusions work very well, and I do think that the conclusions, well two of them at least (one of them happened to go too much into forcing drama for it to be satisfying for me) are satisfying. They give the good end that the watcher wanted with also adding a bit of an emotional flavor to it. There is actually a reason that flows into it happening rather than it just happening.
The art is cute, and the sound is able. I have no complaints about either. I'd actually say the art is one of the strong points of the show as it really helps the cute girls be cute, which is great for a show like this.
If anything I feel like One Room is killed by it being a niche product. I wouldn't recommend this to most people because I doubt most people want what One Room is selling. And that's fine, because it's plot and characters are limited in time and space, and because of it's format it's not designed to work in that way. But if you're in that niche and that's what you want I recommend you check it out.
One Room is not some grandiose work of art, nor is it any substance full. It's designed for girl-loving people to imagine themselves with these girls in their one room. And for that it does a pretty good job.
