First tag:
Too much going on. There is too much attention attracted towards the background, which makes it look messy.
I think if those C4D's or whatever that mess is, was removed from the background, and it was blurred a little, with some lighting changes, it would look good.
Should have focused on the fire more, and expanded the effects around it, would look great.
Second tag:
Looks good, however, should have some lighting corrections to make it look good.
For example, there is brightness at the bottom right part of the canvas, which takes attention away from the focal (which I'm guessing was supposed to be the render).
Third tag:
I like the smudging, I think you made the canvas too big for this signature, because all there is added is the ball of blue "energy" (you could call it that, I guess),
and there is quite a large amount of open space which is just empty, which makes it look "unbalanced". However that could also be fixed, if the background was blurred, and darkened, with a light source shining down from top of the render.