The Chorus is bombarded with psychological and theoretical math terminologies.
I just started playing it, it's awesome. In my opinion.
You play as the reincarnation of Abel! (Though this is unknown in the beginning.)
You discover a device that help you summon demons and foretell future events, which you use to protect yourself from the demon outbreak in Shibuya, as Shibuya is in lockdown due to the government preventing the demon from spreading. You see the numbers above people's head called death clocks which tell how many days they have to live. You have 0. But you can change your destiny! Everyone in Shibuya has only 6 days to live, what will happen then? God's Judgement! As the demons appearances are a test of human's worthiness. The main character has multiple choices, which will affect the ending, Will you become the messiah? the protector of humanity? the king of hell? I just love it.