My bad... All this time I thought he was Polish, but he is from Indonesia. Too similar flags... 
Similar in an upside-down world, you mean. And yes, pun intended.
On-topic:
Aether seems fitting, time too. I like Entropy. But Death and Gravity feels too off thematically. While i know it's mainly the design, you should maybe try a more "thematic" approach. I can't feel Death's decay or Gravity's order, for example. Different from Aether (semi chaotic particle), Entropy (self-explanatory), or Time (has this "time flows" feeling).
Life's good, it feels full of energy and... root. Yeah. Greeny swirly vital DNA, or whatever. Nice.
Try Darkness, and maybe try making it based on a spilled Liquid Shadow. Black dust/ink/particle swirling seems good and is thematic.
I would try, maybe even today i will make something with Darkness. And about Death and Gravity, in making
wallpaper I was thinking about great strength, concentrated in a small point. (inspired by the black hole). In my opinion its good enough, but i can make 2nd
one, if you want.
About
wallpaper, i was thinking about silence and solitude. I think it is quite good, and that there are no changes needed.
BTW, I will try everything to make
wallpaper looked like Liqiud Shadow. Trust me.
The elemental icons are not integrated well here, but you can easily solve that in GIMP with some effects. Basically you want to soften the edges so they don't look so copypasted in there.
Youre right. Need still to improve my skills with Gimp, but i would try. ^.^
I bet parabolic 
would look cool...
With enough time, i would make
wallpaper too, nice idea. ^^
Thanks for good feedback.
