What if God was actually the evil one and Satan was in fact good? After all, God is responsible for billions upon billions deaths, while Satan is responsible for only 10, all of which God commanded of him. If something bad happens like an earthquake or a Tsunami, we tend to call it 'an act of god' not an 'act of the devil'. Why?

It beggars my belief that millions of 'believers' claim that god is good, when the 'evidence' from his alleged behaviours and teachings is so comprehensively the opposite. Throughout the bible there are numerous accounts of god dishing out divine punishment by way of genocide, plagues, ethnic cleansing, and the like. If the bible were the word of god, then god supports infanticide, slavery, torture genocide and all manner of death destruction and suffering. I do not know of any mention of the devil being blamed for such things.
God is clearly a tyrant. He has committed many acts of evil, and somehow managed to amass an incredible following. That means God must be the ultimate deceiver. He has painted Satan as the deceiver to disguise his own faults and gain worshipers in a classic manner. 

Satan is the only deity who truly stands for free will. God threatens us with punishments for not adhering to his wishes. But Satan tells us that we should enjoy our lives and be happy and free to do what we think is right.

I don't believe in god or the devil. I do believe in good and evil. When I was at school we read John MIlton's Paradise Lost. It is a poem in which the devil persuasively argues that he is the victim (must be a scouser) and that he was hard done by god for simply exercising his free will.

The devil's argument follows closely to the ideas in your post. However those who are religious would point out that Milton is actually saying that the devil is a liar, an attractive and plausible one as the best liars are.

One more point

The whole poem really has to be a justification (successful or not) of God's ways. But is it? Is Milton really putting himself where he can vindicate God's perspective on things?
Or, is it just one of the first examples of "Fake news"?

Yeah but I think ‘God Lite’ later on in the Bible (New Testament) was a bit more touchy-feely.

Palace since 19 August 1972. Palace 1 (Tony Taylor) Liverpool 1 (Emlyn Hughes)

All you heretics, apostates and blasphemers are going to burn in hell.

Why do we exist?

Keep asking yourself the same question and you will eventually find the answer?