Not even his platform is largely different from the Republican platform.
Both favor imperialism and nation building, the expanse of federal government authority at the expense of the states, continuation of mass surveillance and Patriot Act type measures, Keynesian economic policy, a mass of economic regulations that result in general job loss and perks for large corporations, wrongheaded public spending programs, disregard for civil liberties, deficit spending, inflationary monetary policy, militarization of the police, total disregard for the Constitution, etc.
In the real, substantive issues dealing with the functions and scope of government they are identical. They differ only in a few, heavily publicized issues that are disagreed upon as a matter of political theater - like gay marriage, or which country to foist our imperialism upon, or which group of society we should steal from. The question is never raised that maybe we shouldn't be imperialistic or thieves at all. Partisan politics is a great big false dichotomy with one brand of centralized government at one side and another brand of centralized government at the other. It is a sham.