In Ezekiel, the House of Israel betrays God by (metaphorically) cheating on him with other gods: Egyptian gods, Assyrian gods, Babylonian gods… pretty much whoever's around. But while the House of Israel and its people—prophets, royal officials, priests, and everybody else—seem to be the experts at the betrayal game, others seem to be pretty good at it too. The King of Tyre , for example. As a result, God pours out triple-doses of wrath on everybody.
What really is betrayal in God's eyes, according to Ezekiel? Basically, it's not keeping your attention on what's really important and letting it stray off in a thousand selfish directions. In this case, Ezekiel considers God himself to be what's really important.
Although Ezekiel is a pretty wrath-intensive book, it also has compassion and forgiveness in evidence. God eventually promises that he'll be a kind shepherd who will lead his people out of darkness. However, Ezekiel's version of God isn't really merciful in the commonly accepted, modern day sense of the word "mercy." He's not going to forgive anyone unless they basically deserve it. He's still very concerned with justice, with measuring out what people can and can't have. So, there aren't any "Get Out of Jail" free cards in this book. Suffering and punishment pay for everything.
At the same time, God says that children won't be punished for the sins of their parents; everyone will be judged based only on their own deeds. He also promises that he'll forgive wicked people for all their sins if they start to shape us, so they won't have to suffer the consequences of their previous actions. So he strikes a kind of compromise between justice and mercy.
Ezekiel's God has big plans for Israel's future—well, fairly big plans. They're not quite the visions of cosmic peace that Isaiah has, but they're still pretty good. Ezekiel envisions a time where a stream of freshening water from under the Temple will bring the Dead Sea to life symbolizing the restoration of the people who re-commit themselves to God. He also sees prosperity and plenty, in addition to having David (or one of his righteous descendants) as a king again.
He also envisions a valley full of "dry bones" where the dead return to life. This may be a political metaphor for the return of the House of Israel to vitality, but it has greater meaning. It foreshadows the idea of a real resurrection of the dead, which will play such a crucial role in Judaism and Christianity.
Ezekiel's God is really big on judgment—it's his most essential, defining jam. Since the people keep disobeying his laws and pursuing other gods, God decides to hit them with wave after wave of judgment and wrath. Before things get any better, they need to get way, way worse. But God's justice isn't only about making people suffer for their sins, it also seems to help rehabilitate them, preparing the ground for their triumphant return and restoration to goodness and glory.
Ezekiel himself suffers, almost like a kind of voodoo doll, all the pains that Israel itself will undergo: he's an individual who exemplifies God's judgments on the nations. It's an "I feel your pain" kind of situation. His wife dies, he has to eat Ezekiel bread laying on his side, etc. All of these things represent the harsh judgments that the House of Israel will face.
In Ezekiel, human power's no match for divine power, which totally crushes it. All the human rulers, from the Kings of Judah to the King of Tyre to the Pharaoh of Egypt have to deal with God's wrath. It seems that Biblical kings who keep faith in God's power still manage to keep their own. Unfortunately, none of those guys show up in the book of Ezekiel. God is able to demonstrate how powerless kings and princes really are, so it's pointless for Israel to look to them for their help.
Ezekiel seems to have access to a totally different realm of reality. He has mystical visions. He's magically transported in an instant from Babylon to Jerusalem and back. He remains immobilized for months on end. Of course, some people would say he was crazy, but he's definitely not just spouting nonsense—even if he sees things that seem shocking or strange, like four-faced creatures and wheels full of eyes. If you look for it, there's meaning in the visions that's consistent with what other prophets have said about the fate of Israel, so we can't just write them off as meaningless hallucinations.
The dramatic language of the book conveys just how different the prophet's experience is from that of ours. Even though otherworldly experiences are hard to understand, many people seem to seek them out. Remember the '60s? Oh, wait, you don't. But the whole psychedelic movement was an effort to get to another level of consciousness, either through hallucinogenic drugs like LSD and mescaline or safer techniques like meditation. And of course, all religions have mystical traditions where believers try to reach a different level of experience of God.