Ignore... if we wanted a wall like the original we would take a screenshot and put it as wallpaper

you used stripes as the BG, don't, try some kind of pattern
he is dressed with his kimono and with one inner shirt, don't put the pattern all over it, just on the kimono
you missed the color on the skin on the right eye
make the shapes more flowed, you still seem to be afraid of vectoring
in the hair, why don't you try the same coloring method as in the anime?
it has some kinda of net and then gradient on top, try it
give some lens to his glasses, make one white shape and lower its opacity, work with the shadows then
and put the title in japanese, will look a lot better
almost forgot, remove the doubled lines, they are confusing