I like most the thubnail but 2x is ok too.

No, I am not a PJ administrator, but active community members have the option to share their opinion with the actual moderators by a voting system.

That Feebol was born that way is cool, that you like it double pixel styled is cool as well, although accepted double pixel work often has a high quality or a special reason. Your avatar does have a double pixel function in my opinion.
Anyway, what bothered me most is the white background, and the colors just do not seem the best to me, but that is all the artists choice.
At the end everything will be reviewed by a moderator, but out of experience I can say it might take a long time before they accept this one (or reject it), because they wont be sure what to do with it, and will wait for more votes.

Are you a PJ administrator? Sorry, I'm new here. Does your 'no' vote mean it won't get put in the gallery?

It was designed to be viewed low res and I have had double pixel submissions accepted before. If I make the white background transparent and don't double pixel the image would that make it acceptable?

What's wrong with the colours? Feefol was born that way :)

Dithered shadow would do fine without the background. The animation is great (really), but the colors, the background and the double pixels made me vote a no for now..