Hen Zemi is an OVA based on its original manga of the same title, which stands for Hentai Seiri Seminar (変態生理ゼミナール, Abnormal Physiology Seminar). Some people may describe this show as R-Rated version of Seitokai Yakuindomo, and it is partly true. However, instead of high school students making frivolous jokes about human sexuality, you will see a team of college students doing live-experience research on perverted behaviors of human under Professor Meshiya’s guidance. I won’t go into specific details what they study for the sake of modesty. Basically, every student in the seminar, including girls, is a pervert of some kind; in a way, they are kinda of guinea pigs for Professor Meshiya’s grand experiment. The only exception is Nanako Matsutaka, voiced by Kana Hanazawa, an innocent-looking girl who is the only person without any perverted traits. Think of her as a control group in a scientific experiment, and that’s why Professor Meshiya specifically recruited her.
Despite the disturbing content, the XEBEC’s production quality of this OAD was surprisingly good. Even though the OP and ED theme resemble much like SHAFT’s Pani Poni Dash’s OP, they have stylish look and makes a good use of pastel color. For some reason, the OP music sounds like a one from a magical girl anime as it reminded me of Puririn from Welcome to NHK. Oh, the ED even has a reference to the famous music video Baby Baby Baby! :) Even though the characters look very simple and minimalistic, they have very dynamic facial expressions and their body movements are well-animated. It’s probably thanks to the fact that this show is a single-episode OVA, which means the production studio had plenty of time to work on it. You’ll be actually surprised that a show as dirty and perverted as this one has some artistic merit to be appreciated. Oh, if you wonder why this show has a SHAFT-like visual style, it’s because Hen Zemi is directed by Ryouki Kamitsubo, who has worked on SHAFT’s Ef – a tale of stories and Hidamari Sketch as a director under the guidance of Akiyuki Shinbo.
Conclusion: If you have an interest in Japanese pornography culture for some reason, you may want to check out this show. (Whether the purpose is education or entertainment is up to you). Also, avid fans of Kana Hanazawa may want to check this show, because you will hear some embarrassing lines that you wouldn’t normally expect to hear from her. Otherwise, you better stay away from this anime before it ruins your appetite for your dinner.
Source: https://blogs.emory.edu/animec/2010/07/24/hen-zemi-ova/