Well you wanted criticism,... Here you have it: first off, I'd say these are Masterpieces of their own, I commend you on this Job well done Esky, second, The Criticism,
The First one, it looks gorgeous, but the shadow is a tad off, it needs a little bit more shadow on the dark side, to portray the nights more exact.
The second one, The water Texture, It's Nice, really. But it looks more like the inner workings of my Brain, too much chaos (IMO ofcourse) if you make it a tad more symmetrical, it would look far betterin my view, it would give you a literal feeling along the lines of "to go with the flow" so to speak.
The third one, The solar Flare, OK. TBH I found the First two better then this one, why I hear you ask?? Simple, I think that its just a star/our sun, with a ring of gas around it, instead of portraying the Feary essence of a solar Flare, If you could make it Have more Flames on the surface, searing across, it would look a bit more "Passionate" and really catch the Spirit of the Fury.
The Fourth, OK Warp, Warp has a "symmetricalness" yet at the same time it hasn't, it is order and Chaos at the same time, and its simply maginificent.
There is your "Critique" I hope it is of your liking, It's the best i could come up with, if you have problems with it let me know, and I think that with your vision on it I can come a bit farther then just my look upon it, Keep up the good work, you mad aussie