Can you please give feedback on this? :(

[SpritZ]

Hello, I have a question for you guys. What do you think of this sprite sheet?



It is probably bad. It's mostly a recolor. But I changed a few minor things like the shape of the nose a bit and the eyes. Can you please tell me what went wrong? Maybe I'm not cut out for this thing.. It kinda discourages me.

A while back before Sonic Mania came out I worked hard on trying to remake the sprites from the Sonic Mania reveal trailer and Hedgehog Dance Party. But it was rejected for not being completed. But when Sonic Mania finally came out, people already published the sprites I was working on to the game.

But now my Wiggler Sprite Sheet got rejected for this. 

Your sheet was not accepted for the following reasons:

• The sheet does not meet quality standards for the Custom / Edited section. We are always happy to see people who want to do custom work and, as a community, strive to help artists grow. This sheet does not currently meet our quality standards but we'd love to help you improve so head over to the Spriting and Pixel Art board and post your sheet there for some constructive feedback and suggestions.
  
• Sorry we can’t accept things that are recolors of existing sprites.
  

I have no idea what they mean by "Quality Standards." Please tell me.

Though I guess I can see where they are coming from. Can anybody please share some tips and tricks on how to improve?

Thanks. -SpritZ