In a nutshell, this is a softcore lesbian erotic anime. Its primary purpose is to arouse the audience; it has no other purpose. The plot serves as little more than a pretext for fanservice-laden fight scenes, hot girl interactions, and almost hentai situations. As this anime demonstrates, "softcore" anime may more frequently afford much better production standards than true hentai anime, which is often stuck with very modest budgets. Personally, I would much prefer see a softcore show with respectable production values than "hardcore" OVAs made from scratch.
As I mentioned before, the action scenes' "Soul Eater, but with orgasms" idea and the tale of a group of girls being stuck on an island are all really just excuses for boobs and yuri, and the characters are mostly there to satisfy particular fetishes. Both the "plot" and the portrayal perform admirably in that aspect.
The explicit scenes tend to look fairly decent, and the character designs are undoubtedly the nicest and most appealing of all the Valkyrie Drive projects. The visuals are pretty nice, however occasionally there is a noticeable lack of polish. Despite not being especially distinctive, they manage to be quite elegant and appealing and have their own distinct appearance and feel, all without the usual VN-esque cheapness frequently found in such anime. The series succeeds in having many truly sensual situations, and the animation is done pretty nicely when it matters.
There's nothing wrong with the sound design; the music and the VA cast both perform admirably, and the required groans are used to good use.
I loved this series in the most ridiculous manner possible because I love well-executed filthy yuri, and considering its goals, that was really all I needed.
