I am looking for a game from the 90's?

that I used to play on the NES. It was a role playing game in which you fought various creatures, then faced a boss at the end of each level that looked like a centaur, or a satyr, or some other Greek type mythological being and with each level you got god-like powers. The game title logo had a planet or some odd looking world. I want to think it had the word God or Quest in the title, but I haven’t been able to find it. I even spent several hours on an eBay game sellers’ site looking for it, but to no avail. I was wondering if any one else remembered it, or maybe played it.