Nice motif. Nasty banding that can be fixed easily. You could clean up the edges around the moon using the darker yellow along the edges of the guy for AA.
The 'glow' doesn't work as glow - it just makes everything feel blurry. It also makes jags more prominent, especially around the moon.
Isn't this just your past work with a moon around it?
The outline with the lighter color is banding and it does not help the piece. If you want to AA, you can make it mostly the black color of the man and only add in that lighter color in certain spots to smooth out the figure.
Right now it just blurs the figure.
Oddly enough all I can picture here is the Paper Tube Samarai