I'm kind of confused here... I don't know what happened lately, but it seems that no matter what I submit, it always needs revision because of the score. No one even leaves any comments, except for one person who thought that I needed to spend more time on it... witch isn't very helpful, since I really don't time myself (I'm done when my art turns out how I wanted it to), plus I used all the time I was given (weekly challenge). Is it really just me?

well as members were only able to see what is accepted, the piece that aren't accepted are hidden to everyone except you. because you were the person who submitted it.

personally if i were you, i'd be putting more time into shading and picking your colors. alot of the stuff in your peices have dull and boring colors. they generally don't work well with each other either. to help fix this, i would recommend looking at other peoples artwork, look at there colors and check the values. look at alot of peices and then use the knowledge you gained from observing this and it should help you pick better colors. if not look up tutorials.

secondly your shading lacks texture and your work looks very flat all the time. i can't really suggest how to fix this, shading is shading, its taught by practising mostly. so....

yeah, hopefully this has helped you figure out how to improve your work :)