There is some symbolism in this game. RELIGION symbolism...
At the beginning of the game you are presented to something who later reveals itself as "TANAS".
He claims that has "awakened" you and gave you "free will" through his "fruit of knowledge". TANAS warns you about a tyrant that lives above and can remove your ability to question and to think for yourself.
When you reach the outside world you are presented to "GODAMI", a being that refers to you as "slave". This tyrant gives you some orders and you may choose to obey, or ignore them. GODAMI sends you to the "ABYSS" again and commands you to refuse anything TANAS may offer.
May I start? Great... Oh where to begin? TANAS is a reference to SATAN and GODAMI is a reference to GOD (GODAMI = I am God). The game is set in a post-apocalyptic world and represents what should be like after the "Battle between Heaven and Hell" (by the way the game's name is a reference to this). The fruit that gave you the ability to think is more likely a reference to the Apple of Eden which was eaten by Eve (by the way your android's name is Eve :D).
In the game you must choose between obeying God, Satan, none or both (the last one is kinda weird). God is shown as a tyrant who executes anything that defies his laws and slaves everything. Satan is shown as a trickery creature that seduces you with gifts, only to make you its slave in the end.
Want more polemic stuff? Ok! GODAMI's executioners are more likely God's angels (they even wear halos). He is afraid of anything that can make its own decisions and wants to kill those things. As TANAS lacks of an army, he must find those androids with free will and make them as his slaves.
In real life, religion forces people to submit to God and refuse Satan's gifts. Pretty much what happens in this game but with different names or else people wouldn't play it. The truth is, that the game's endings show that both "tyrants" want to slave you and your best choice is to obey none.
Now now christians (or satanists), please hold your torches and pitchforkes. I mean no harm to any religion with this review (even though I don't believe in God and agree completely with the image this game has of Him). You have the right to believe in anything you want to, and if anyone else forces you into it's religion, just punch'em in da face :D. But don't mistake forcing with arguing, for there is nothing wrong with a healthy discussion that doesn't ends friendships.
Oh! What is that? This a review not a religion discussing forum? Please forgive me, I didn't mean to. Here's the review:
Awesome gameplay, story, soundtrack (The musics are AWESOMEEEEE) and specially the story. The controls are a little awkward and take some time to respond, but it only affects combat and the game doesn't has much of it. I am leaving a 5 Stars, and that is because I am what you call "easy to please". Thank you for reading this far, sorry for any grammar mistakes (I am Brazilian and most people around here can't even pronounce "green" :D brbrbrbrbr) because I know there are a lot. And remember... THAT IS JUST A THEORY... A GAME THEORY, thanks for reading :3