The series turned out well when referring back to the manga; there are no major deviations to the characters or story. The art style works well for the genre and the soundtrack is rather enjoyable, most notably the opening and ending sequences. For those who have not watched it, the main series does not provide a complete ending, so don't forget to watch the OVA continuation Redial to get peace of mind.

There is also a live-action TV series adaptation which isn't too bad, but is flawed and makes a lot of minor, and even some major changes to the original plot. As for whether I would recommend checking out the live-action series, I would only recommend it for those who have the spare time and very much enjoyed the original series and don't mind watching the story unfold in a different direction.

As for recommendations for different series that are similar, I would suggest Btooom! if you are seeking another battle-royale-esque survival series, or Eden of the East for a non-violent series whereby you have a selection a people pitted against each other to decide who among them will reign supreme and make a lasting impact on life as they know it.

Saw demo-senpai make a review on this but with the name "Future Diary". Seems, okay I guess. Definitely one of those "shock" anime that aren't super great but hook you in with its craziness. I'll probably give it a shot as it does look pretty solid. I'm pretty sure its on netflix too.

I got so so so mad about the ending of this havent seen the extra bit yet though