If you watch this you'll likely end up questioning yourself, your friends or generally what person you are and how everyone around is or would be.. However, while I recommend watching this, since it's a great watch with surprises, ups and downs and the necessary deep matters/questioning that arises due to the base of it - my main reservation is that it ends on a cliffhanger.
This will likely not get a second season, yet there is a manga that will be finished soon, if it isn't already - hence no more adaptations. It's an ad for the manga, so if you don't mind that and like shows that are game based, or morally challenging, like X&Y from not long ago, then give it a go and just switch over to the manga. Be warned that it gets heavy.
