Totalitarian governments are governments that try to keep control over almost every aspect of the lives of the people they rule. Because of this, you could describe as "controlling."
Totalitarian governments are not willing to allow people to disagree with what the leaders say. Therefore, you can call them "intolerant."
Totalitarian governments are willing to take harsh measures to punish those who seem to go against what the government wants. Therefore, you could call them "oppressive" or "ruthless" or even "brutal."
Totalitarian governments have no regard for human rights. If you are so inclined, you could go so far as to say that they are "evil."