Hi finaga
Don't have much time but I made this edit for you really quick:
Basically don't be afraid to use the dark colours or AA, no need for dithering. Some broken outlines that could be fixed as well as some lightning. The main problem with your
characters is that they don't
have any shades noticable. the dots of dithering can barely be counted. Be brave, use all colours even the dark ones on larger surfaces.