But if you're meticulous about these details like me (and a lot of other geeks out there), THESE THINGS MATTER!!! :D
Imagine that Zeus is "King" of the gods and he relies on prayer for power. -.- Heck, if he has eons of experience with humans he can just do the "Black and White" thing and create miracles or disasters. Those are the two basic methods for creating belief - fear and wonderment.
There's no rule saying that they can't show themselves to humans (unlike other gods). So theoretically he can just become giant Mega-Zeus and scare the bejeezus out of his followers and reduce them to slaves.
Cronus is a titan with intense amazing Cosmic GALACTIC POWER with the namesake of TIME ITSELF!!! Then he's shown to be a walking Volcano Throwing Lava here and there. meh. Story.. it's all about the story. It's just funky if you know the BACKstory. :p READ THE DAMNED BACKSTORY!!