A mixture of the classical drama's incest manga have with the quality (art and animation) as the Bible Black Only series. Let me first talk about the quality (art and animation), it's so well done that I would have rated it higher than Bible Black Only, but since that was my favourite hentai, I can't really do that. Regardless, if you haven't seen that, this should be your delight - but first be warned it does include an incest storyline - unless that's what you like, like me. In my opinion, how well is the art and animation? Well, if I were to compare with normal anime, it would be like a mix of Dragonaut (art of characters) and Eureka Seven (animation).
Now onto the story (with the inclusion of sound). First, don't get fooled by the false information provided on this site about the story. It actually deals with the protagonist and his sister-in-law. The story is as dramatic as incest manga I've read in the past, and the sound is very consistent. It doesn't have over-the-top sound nor is very low-key. A right amount to keep you watching. I would have preffered if it was either a bit longer (more episodes) with more dramatic story or was just only 1 episode long with everything they cover in the OVA combined. It's really hard to explain the story without telling you a summary, so enjoy this on your own.
Lastly, I also would really like to see a sequel to this OVA, if possible. Though, I know it would be hard to continue where it was left off. But I would highly welcome more OVA of the same quality and dramatic story - like if the incest manga's I've read were to be animated. I also would highly recommend this OVA to anyone that likes the incest genre with intense drama about two people who "love" each other.