Your description is too vague.
There are tons of different styles used in those consoles.
If you put side by side, Mortal Kombat (that uses real photo), Earthworm Jim, Streets of Rage, Castle of illusion, Gunstar Heroes, Sonic the Hedgehog (pretty vibrant colour palette) , they all look different.
Post a game that have the closest style that you have in mind.
That'll be easier for the artist to know the exact style you want.
Just my 2 cents.