Here is what I felt made the show unique:
It is a harem anime but unlike I lot of them the main character is not two-timing any girls and he actually picks one for each arc. You will see 4 (technically 5 in the chibi skits at the end) girls get pursued by Haruka and each only one at a time. You get to learn about each girl and the pattern is that Haruka is kind and helps them overcome some problem or trauma and after that they get into a relationship and have sex.
That's basically the plot and though on occasion the sex seems to accentuate the story a bit (like Akira) it felt a bit out of place and rushed and more for fanservice. The one case where the sex affects the story a LOT is in the last two arcs where Haruka starts to realize he is attracted to his sister--more on that later.
The situations each girl is in and some of the problems he helps them through are unique and some of them, like akira, I found particularly heart-touching. After coming to the conclusion of each arc with each girl it appears to reset to a sort of "save point" in the story prior giving Haruka a chance to make a different choice and learn about a different girl. This is why I said it resembles a dating simulator animated. I thought this was rather clever and enjoyed it more then the typical harem style.
Story: 5/10
There isn't a lot of character development because there isn't a lot of episodes devoted to each girl but I was satisfied with the way I got to learn about each person and watch them both change as they interacted with Haruka. They originally, as is often the case, start as somewhat cliched character stereotypes but you get to see them be developed more and feel a greater depth behind each character then is often the case, especially in short anime.
Character Development: 6/10
The art was very pretty. I found the style very appealing and the music choices accentuated the animation well. I watched subtitled so I can't say much about the voice-actors not speaking native Japanese myself.
Art: 8/10
So...on the incest:
The last girl is Haruka's sister Sora, as pretty much everyone should know from any review on here.
It was an interesting final story that added some dimension to them but, unlike a lot of viewers I didn't find it particularly profound and it made me more worried for them. A lot of viewers loved the idea of forbidden love and said this anime was great for raising questions and challenging society. I tend to think they are wrong, but not because society says so. There are some really good reasons why I didn't think the anime developed this as well as they could have. Just raising a touchy subject and simplifying it doesn't make the anime "great". (my thoughts here will be long so skip if you want)
The anime is trying to make the viewer think about societal pressures and if they are arbitrary. If Haruka loves his sister is a sexual relationship ok? How much is? Is loving someone enough to justify resisting society on this issue? It tries very hard to set this up as a situation where Haruka feels powerless in the face of feelings and society is coming between them. But...the anime robs the situation of its complexity by failing to emphasize the choices each character makes and the possible forms of love. And thus makes a fundamental mistake about the nature of it. It also robs the situation of its potential problems by presenting a "happily ever after" choice. Basically Sora and Haruka can move away and go incognito and that's that.
First off, "lust" is not "love", something many people have difficulty recognizing the difference between. I can want to have sex with someone but not love them and want to spend my life with them. Basing a relationship solely on sexual attraction is asking to fail. Similarly, you don't need sexuality to have a good relationship. What matters is the growing intimacy between two people and how they grow to understand and look out for each other. This is what holds relationships together and should be looked for primarily when thinking about making a long-term relationship choice. Sex is the worst glue for a relationship ever, and yet the sister, Sora only seems happy with a physical relationship with her brother? And angry when he is kind and does things for her, makes time for her, but doesn't have sex with her and kiss her? It seems an arbitrary scenario.
When it comes down to it, there are way more choices involved here then the anime makes you think. Being sexually attracted to someone is not love as we can clearly see Haruka could have chosen any of the girls (and does in other arcs). Love is usually not a powerful emotion that you are doomed to follow but fundamentally has choices and complexity.
But the anime doesn't explore this open avenue at all. it basically just shows Haruka realizing he is sexually attracted to his sister after seeing her masturbating and jumping straight to "move to another city and live our life together to escape persecution and our family". Despite the fact that it is clear Sora is not the only person he is attracted too. What Haruka wants is a relationship with his sister. When that is threatened (mainly by Sora's own feelings but also by the potential breakup of them by family members after their parents death) he chooses her. But I don't see why the siblings couldn't insist to their relatives they stay together and expressed that love in a non-sexual way. It felt like a forced plot device. Heck, they could have even continued to live together. It made sense because his sister has health problems and he could keep taking care of her. But the anime made it this "all or nothing" sort of scenario.
Beyond this, I think the focus on physical relationship actually has a very high chance of hurting or destroying their relationship in the long run. Imagine how awkward it will be if this is not a happily ever after story and later one of them wants to explore other relationships again? By making this choice they are setting themselves up for an awkward estrangement in the future made all the more awkward by the fact that they are siblings. Once they've chosen to have sex and be involved in this way, they can never go back to the innocent love of "just being siblings". If something happens and they break up they will be unable to be there for each other in the same way due to this past, losing forever the chance to support each other as just sister/brother. This is made even sadder by the fact that their parents are dead and they have no other family they are close too. At this time after the loss of their parents they both need close family and romantic relationships. They will be healthier with both imho. And it is sad to me to see them rolled into one with the future possibility that they could lose both. I would have loved to see this developed or even considered but it isn't.
TL;DR: I think the anime made the characters seem powerless and two-dimensional by making it seem like they "had no choice" and were "victims" when they really had all the choices. It is a classic "depowering" under the guise of "romance" and something I really don't like seeing. They also failed to address the complex issues of these choices such as the fact that by choosing a sexual relationship the siblings are most likely sacrificing their relationship ever being innocent love again.
