If you're looking for an anime with deep plot, this is definitely not it. But if you love hot girls with supernatural powers fighting it out while stripping each others' clothes off, this anime is for you, at least the first half.
The underlying concept of an all girls anime with extremely lewd, erotic scenes and yet no explicit sex has rarely been done before, and Nanatsu no Taizai was so well executed I was really amazed by it at first. The lewd outfits and erotic scenes including tentacles and aphrodisiacs rivals hentai anime, indeed, this anime turned me on more than any hentai ever has.
However the animation, story, and even erotic content decreased in quality as time went by, and ended with disappointment. I don't know much about directing anime and storyboarding, but the poor animation and still frames in the last few episodes really stuck out. I loved the erotic content so I didn't care for the story, but because even the erotic content was lessened, there was nothing to save the anime in the end.
I was a big fan at the start, and I still love the erotic scenes in the first few episodes that are even better than hentai, and so I still recommend watching the first few episodes, but watching until the end might not be worth your time.
I still give it a high rating of 8/10 for the first few episodes, because I had never seen anything else like it.
