The color hack is only half complete, Asaki still has to change the colors of all the characters.
Other stuff that should be done to this game are:
Give the first part of stage 4 its correct music track.
Give Slash his afro hair from the arcade version:

Restore the missing pain animation for Poison and Roxy from the arcade version:

Restore Jessica's uncensored intro sprite from the Japanese arcade version:

Restore the original enemy sprite that appears after you beat the first bonus stage, they changed it in the GBA version for some reason:

Restore the wooden entrance to the basement on stage 1 from the arcade version:

UPDATE: I changed the wooden entrance image with a different one because the original one got taken down for some reason.
Restore the word "Sexy" on the bathroom stalls on stage 5 from the arcade version:

I think is easier to hack the Japanese version because everything is there, the only thing to do is change the text to English.