Dictionary.com's definition of Theocracy includes:
1. a form of government in which God or a deity is recognized as the supreme civil ruler, the God's or deity's laws being interpreted by the ecclesiastical authorities.
2. a system of government by priests claiming a divine commission.
While I agree with many points of the other answers, I would also suggest that the definition of Theocracy includes a presumption that your super-powered god is not going to turn up and start handing out instructions and awards, along with sores and lightning bolts. Sure, point 1 allows for the possibility that he or she will do so, mostly for the case where average humans claim to be gods, but I don't think anyone actually expects the appearance of All Powerful God A to happen, not the dictionary writers, nor the ruling priests. I would suggest that Theocracy is really either rule by a human claiming to be a god with priests interpreting his or her wishes, or rule by priests claiming a divine commission - the essential point being that there's no actual active divine being in the ruling mix, laying down the law and smiting people.
I would further suggest that if you have a god actively running a state then that would be a different form of government, perhaps a divine monarchy.
1. a state or nation in which the supreme power is actually or nominally lodged in a monarch.
2. supreme power or sovereignty held by a single person.
The fact that the monarch has god-like super-powers is neither here nor there to the definition, though it may well affect the day-to-day reality of the situation.
Of course such a change would allow for some adjustment to some of the answers above, though most of them would stay the same.
Not least, how does the appearance of a god affect how he or she is perceived?
If they are human shaped, then one might start to see them as a super-powered variant on humanity.
Are there limits to their powers (perhaps due to other gods)? So maybe their powers are super, but not god-like - there will be disappointments.
Over time, given humanity's ability to adapt to almost any situation, I would suggest that at a minimum, those close to the gods would start to see them as 'less-than' - what effect would that have? What actions would they take?
And there are other effects, which I will leave to your imagination.