Translation:
The Garden of Eden symbolizes the nomadic, hunter-gatherer lifestyle of pre-agricultural humans. The apple tree represents the invention of agriculture and the deliberate manipulation of nature by humans who dare to pursue knowledge and forsake instinct. Being cast out of the easy-living garden parallels the troubles brought on by civilization and the responsibilities of farming and getting along with large groups of strangers.

God is a metaphor for the entirety of reality conceived as a single entity. Jesus is the logos - humankind's capacity for logic, reason, and the pursuit of truth. Heaven is upward - the sky, in literal terms, but symbolically, the higher aspirations that set humans apart from the rest of the beasts, which are collectively depicted as a human-like figure with horns, hooves, and a tail. This Adversary figure, Satan, represents all of the temptations to revert to our animal instincts which would make living in civilized society impossible.

But we were not really designed to live in cities, so we suffer from our sin of choosing our own Garden of Artifice over God's Garden of Eden. Diabetes, heart disease, cancer, mental illness, wars, famine, epidemics, etc. The Jesus figure represented salvation from these ills which we brought upon ourselves, forgiveness of our sins of self-determination, and eternal liberation from psychological suffering, through the act of transcending our natural identification with ego.

The crucifixion was a means of symbolically showing the path to this transition. Jesus volunteered ( it has to be voluntary ) to face the most horrible and dreaded torture and death known at the time of writing ( which symbolizes facing the scariest thing we humans can face - the dissolution of self ) and demonstrated that it is survivable, and on the other side ( resurrection ) there is no suffering. Life after death translated literally is unrealistic to the modern mind, but life after the death of ego identity is more likely what the stories were really about anyway, and scientifically plausible today.