I think we may be looking at this from too Western a point of view. This game is the product of Japan, where the prevailing religious ethos places more emphasis on balance, awareness, and harmony. The "Entity" in Chrono Trigger is definitely a god, but certainly not in the sense that a Christian would think of when he or she thinks of the idea of "God."
I do not want to oversimplify this as an "East vs. West" difference in thinking, but I do want to point out that, to fathom the Entity, it is very helpful to be mindful of the culture that made this game in the first place. Being aware of this will positively influence our thinking when we talk of death and immortality, and the philosophy of the game seems not to fit prevailing Christian views. Everyone has a sense of the religious Divine, whether or not they believe it really exists, but those who do believe in it will interpret it in their own way...and often with striking differences from one another.
Edit: Clarity, spelling