I recompiled Mame and *just* changed the lines for Galaga.  As far as I'm concerned, now that *all* the sounds have been emulated, and that the starfield is now correct, it has been emulated correctly.
You have to change this in galaga.c:
GAMEX(1981, galaga,   0,       galaga,  galaga,   galaga,  ROT90, "Namco", "Galaga (Namco rev. B)", GAME_IMPERFECT_GRAPHICS )
GAMEX(1981, galagao,  galaga,  galaga,  galaga,   galaga,  ROT90, "Namco", "Galaga (Namco)", GAME_IMPERFECT_GRAPHICS )
GAMEX(1981, galagamw, galaga,  galaga,  galagamw, galaga,  ROT90, "[Namco] (Midway license)", "Galaga (Midway set 1)", GAME_IMPERFECT_GRAPHICS )
GAMEX(1981, galagamk, galaga,  galaga,  galaga,   galaga,  ROT90, "[Namco] (Midway license)", "Galaga (Midway set 2)", GAME_IMPERFECT_GRAPHICS )
GAMEX(1981, gallag,   galaga,  galagab, galaga,   galaga,  ROT90, "bootleg", "Gallag", GAME_IMPERFECT_GRAPHICS )
GAMEX(1984, gatsbee,  galaga,  galagab, galaga,   gatsbee, ROT90, "hack", "Gatsbee", GAME_IMPERFECT_GRAPHICS )
to this:
GAME(1981, galaga,   0,       galaga,  galaga,   galaga,  ROT90, "Namco", "Galaga (Namco rev. B)" )
GAME(1981, galagao,  galaga,  galaga,  galaga,   galaga,  ROT90, "Namco", "Galaga (Namco)" )
GAME(1981, galagamw, galaga,  galaga,  galagamw, galaga,  ROT90, "[Namco] (Midway license)", "Galaga (Midway set 1)" )
GAME(1981, galagamk, galaga,  galaga,  galaga,   galaga,  ROT90, "[Namco] (Midway license)", "Galaga (Midway set 2)" )
GAME(1981, gallag,   galaga,  galagab, galaga,   galaga,  ROT90, "bootleg", "Gallag" )
GAME(1984, gatsbee,  galaga,  galagab, galaga,   gatsbee, ROT90, "hack", "Gatsbee" )