I played with the GAMMA to see the actual DIO face befor he is oficcialy presented in the anime.

Notes:

So… i decided to see what is the actual DIO face in that shadow, so i augmented the gamma from 1.0 to 5.0 of the original image
PS: i dunno what the f--- is the gamma, i just modified in libreoffice, and gess what…IT JUST WORKS!
PS2: Maybe you will feel spoiled, but since is an 80's manga and a 2015's Anime..