Hi there!
I received this message about the pixelart I'm trying to submit:

REASON: Any art you post should be PIXEL ART! Pixel art implies that each pixel is placed by hand (no filters, paintbrushes, gradient fills, etc).

This is the picture
Here's a close up

So I would like to know if you please could explain me further the reasons why my drawing needs revision so I won't make the same mistake in the future.

However, I guarantee this is a pixelart. I made it myself last summer for a Kickstarter campaign. All the textures, colors, effects... I made them myself (except for the rough texture of the background, for that texture I used some pixelart Krita brushes, if that is the problem I could fix it). I draw shadow on my pixelarts with that screentone style dot by dot because I only use the Game Boy Color palette and also I was requested to draw the ghost like that.

I hope I've explained myself well, English isn't my first language and I'm bad at learning new languages, but I'm trying my best.
Thank you so much for your time.

Hi Hapiel! Thank you for taking the time to answer me.
It's OK if you didn't leave a note, I understand that all the moderators here are busy and they need to take care of their own things, also I don't mind coming to the forum to solve my doubts.

I think I've understand the problem, so I'm gonna submit an edited version with a better resolution and less elements, which I hope it'll be good enough to be approved because I really like that pixelart.

Sorry for troubling you.