ITT, Pastel from Konami's Twinbee series. She's so very cute! Sadly, all I have of her anymore is screenshots from MAME. Long ago (like, back in the late 1990s) there was a terrific Japanese site that was nothing but one artist's fanart of her (everything from good /c/lean fun to very /h/ot stuff indeed) but it seems to have disappeared from the Web years ago, and I must have lost all the pics I saved from there in one of many subsequent PC upgrades :(
The only Pastel pic I have that isn't a low-resolution screenshot...