In what ways is Heavenly-eternal life the opposite of earthly-mortal life?

In this earthly mortal life; the deep problem is not change but loss; not that things are always changing, but that this change is so often a matter of degeneration, disease and death. In brief, this is a world ruled by entropy. 

But if we choose that Heavenly eternal life beyond the transformation that is death; we inhabit a world ruled by creation rather than entropy. It is a changing world; but a world where change preserves that which is good, where change is a building rather than destroying, where instead of death there is eternal life.  

In Heaven - instead of degeneration; there is increasing ability, functionality and knowledge. This is theosis, or deification - becoming more god-like.  

In essence there is a transformation from a world dominated by chaos to a world dominated by creation. The difference is love - since creation comes from love, and is made possible by love. 

Mortal life comes between the first transformation of incarnation, when our spirits become embodied; and the second transformation of death, when we may choose the permanent embodied life of resurrection. All people experience these potential transformations - what varies is the gap between them - the gap of mortal-life. 

Our mortal life is often very short (e.g. the time between incarnation and death still in the womb, or at birth, or infancy - these account for most human lives in history); but may be many decades long. 

The first transformation of being incarnated is what enables creativity.

(Pre-mortal angelic spirits are not creative; but live passively and unconsciously, automatically-obedient). 

And it is the second transformation of death that enables creativity to be permanent and thus divine. 

(This happens in consequence of the resurrected Man having made a permanent commitment to live by love. Insofar as this state may temporarily be attained in mortal life - permanent creation may be achieved, but the ability of people to know this creation, remains subject to entropic change.) 

Note: Why cannot demons create? That demons cannot create is a frequent insight. Assuming (as I do) that it is correct, it is a consequence of demons being incapable of love; either of being incapable love or of having made a permanent commitment to reject love. Demons can only, therefore, simulate a fake creativity - by mechanisms such as extrapolation, interpolation, novel combinations, inversions etc. - i.e. exactly like the typical fake-creative (often evil-motivated) products of fashion, journalism and advertising. It also explains why demons are keen to enlist semi-corrupt humans to their causes, since they remain capable of creativity. Creation comes from love, and cannot be wholly-evil - even when creative individuals (including geniuses, such as Picasso or Freud) are net-evil-motivated.  

Further Note: What is the purpose of mortal life on earth - given that everything comes-to-nothing, sooner-or-later? Given that every-thing perishes, in the end? The purpose of life of earth is not given nor automatic, but needs to be chosen consciously; and what must be chosen for life to have purpose, is to value love intrinsically and for itself.  A child may do this unconsciously and passively; but an adult needs to make a conscious choice of love - and needs (because of entropy) to keep choosing.