Long time no see, Sqay. Not sure if you remember me, It's baroko.
You've improved a lot, nice job.
As for feedback, you need to work on the lighting on your pieces to make it more cohesive.
Make use of cool and warm shadows/lighting, implement blurs to create more depth, to not overload the image and direct your viewers eye.
In the first image manipulation:
There's a strong light is coming from the window which is directed towards the floor.
Since this light is hitting the floor there will be a bounce light coming from the floor on the character itself.
Also making use of a vignette effect will put more emphasis on the focal point, same with bringing a blur.
(quick edit) Gave it cool shadows and warm lighting, brought in a bit of bounce light, followed the light from the window, brought in a vignette effect to create more emphasis and made use of a gaussian blur.
The 2nd image is missing depth overal, there's no shadows of the person himself nor is the yellow light affecting his skin etc (Only thing that's being effected is the pants)
I'm assuming this was intentional, but just wanted to mention it incase.
The fourth image (The futurustic one):
It doesn't feel cohesive at all and the perspective overall doesn't add up. The robot in the front feels so awkward and the red light thats being emit from it is nowhere seen on the rest of the canvas
The sixth image(Balloon one):
The direction of the light thats coming from the cellphone isn't adding up. It's stretched out so it can fit the woman in this case.
Don't have more time to write more since i gotta go :c
Eitherway nice work, love the vector stuff especially the luigi one
Hope to see you post more frequent.