Yes it is very different. No Christian empire could have done what the statists do. It is a different system.

Totalitarianism is a term employed by political scientists, especially those in the field of comparative politics, to describe modern regimes in which the state regulates nearly every aspect of public and private behavior. Totalitarianism emerged in the twentieth century because the means for total social control did not exist before that time. These systems moved beyond authoritarian control. They attempted to mold citizens into a certain desirable type, whether they be proletarian laborer or pure Aryan. In this regard, these new totalitarian systems represented a new political phenomena that moved beyond previous state ends.

[newworldencyclopedia.org]

Stalinism has been described as being synonymous with totalitarianism, or a tyrannical regime.

Maoism has been described as being synonymous with totalitarianism, or a tyrannical regime.

Cambodia became known as the site of the "The Killing Fields" genocide from 1975 to 1979, when range from 1.7 to 2.5 million out of a 1975 population of roughly 8 million, were murdered by or died under communist Pol Pot's Khmer Rouge regime. Some historians have compared Cambodia under the Khmer Rouge to Germany under Adolf Hitler, when the Nazis murdered six million Jews during the Holocaust.

Between 1939 and 1945, the SS, assisted by collaborationist governments and recruits from occupied countries, systematically killed about 11 million people, including about 6 million Jews, in concentration camps, ghettos, and mass executions, or through less systematic methods elsewhere. Besides being gassed to death, many also died of starvation and disease while working as slave laborers. Along with Jews, non-Jewish Poles (over 3 million of whom died), alleged communists, political opposition, members of resistance groups, resisting Roman Catholics and Protestants, homosexuals, Roma, the physically handicapped and mentally retarded, Soviet prisoners of war, Jehovah's Witnesses, anti-Nazi clergy, trade unionists, and psychiatric patients were killed. This industrial-scale genocide in Europe is referred to as the Holocaust (the term is also used by some authors in a narrower sense, to refer specifically to the unprecedented destruction of European Jewry in particular).

The massacres that led to the coining of the word "genocide" (the Endlösung der jüdischen Frage or "Final Solution of the Jewish Question" ) were planned and ordered by leading Nazis, with Heinrich Himmler playing a key role. While no specific order from Hitler authorizing the mass killing of the Jews has surfaced, there is documentation showing that he approved the Einsatzgruppen and the evidence also suggests that sometime in the fall of 1941, Himmler and Hitler agreed in principle on mass extermination by gassing. During interrogations by Soviet intelligence officers declassified over 50 years later, Hitler's valet Heinz Linge and his military aide Otto Gunsche said Hitler had "pored over the first blueprints of gas chambers."

To make for smoother intra-governmental cooperation in the implementation of this "Final Solution of the Jewish Question," the Wannsee Conference was held near Berlin on January 20, 1942, with 15 senior officials participating, led by Reinhard Heydrich and Adolf Eichmann. The records of this meeting provide the clearest evidence of central planning for the Holocaust. Days later, on February 22, Hitler was recorded saying to his closest associates, "we shall regain our health only by eliminating the Jew."

The term totalitarianism has been used to describe regimes that fight political dissent through violence, terror, imprisonment, and killings in an attempt to establish and maintain total control over the population. Not only is it physical, but it is also psychological. Typically, these repressive totalitarian methods are justified as necessary sacrifices for the greater good on the path to utopia. In this context, proven methods that worked can be found in various totalitarian regimes, justification is often the same story about greater good or sometimes called common good, but what represents utopia is particular to each regime. National Socialism, Communism, Technocracy etc.

The road to hell is paved with good intentions is a proverb or aphorism. An alternative form is "Hell is full of good meanings, but heaven is full of good works" The Nazi concentration camps were created to hold so-called "racially undesirable elements" of German society. The GULAG system was introduced in order to isolate disloyal elements not contributing to the dictatorship of the proletariat. The harm done is clearly seen, and acknowledged, but is written off as a 'price worth paying'.

Totalitarianism is best understood as any system of political ideas that is both thoroughly dictatorial and utopian, embodied in the state religion of Statism. The managerial State apparatus takes over the role of deity.

It is an ideal type of governing notion, and as such, it cannot be realised perfectly.

Faced with the brutal reality of paradigmatic cases like Stalin’s USSR and Nazi Germany, philosophers, political theorists and social scientists have felt not just intellectually motivated but morally compelled to explain the causes and implications of totalitarianism. This has been in part an attempt to explain the socio-political phenomenon in itself, as well to develop an intellectual tool in the arsenal of democracy.

Diverse philosophical perspectives have been employed. They share the important common denominator of an appeal to the value of human life, critical thought, and a pluralistic society. Many of the key figures among the anti-totalitarian thinkers discussed here were European Jewish refugees who escaped totalitarian systems. Many who work on this question have been motivated by a desire to come to grips, philosophically, with what is undoubtedly the greatest intellectual justification for mass murder in history: the twentieth century totalitarian state.

• Internet Encyclopedia of Philosophy, a peer-reviewed academic resource | [iep.utm.edu]

"Although there were important differences between . . . totalitarian regimes, they drew from a common well of enthusiasm, and shared such heretical goals (or rather temptations) as fashioning “new men” or establishing heaven on earth. They metabolised the religious instinct." —Michael Burleigh

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“Humankind has long since become accustomed to the mass destruction of those identified as enemy combatants—and the enslavement of others taken in war. In the past, millions have been put to the sword arbitrarily, because of their ethnic origin or their religious convictions. But it was the twentieth century that managed to bring even more capriciousness and inhumanity to the mayhem. By the mid-twentieth century, mass murder came to typify an entire class of political regimes.

Even before the coming of the Second World War, millions of citizens were destroyed by those who governed, even though their rulers were nominally at peace with everyone. Untold numbers were threatened with ‘shunning,’ incarceration, expulsion, or death—because of membership in a proscribed class, ethnic, or religious community. However prepared those threatened might have been to abandon those identities—to become whatever they wished by those who ruled—that possibility was foreclosed. Those afflicted with ‘counterrevolutionary class consciousness’ could do little, if anything, to have themselves restored to good favor. Those so unfortunate as to have ‘bourgeois’—landlord or capitalist—backgrounds were denied schooling or employment, and were often marked for destruction. Rulers sometimes sentenced them to thankless labor, exiled them, transported them, incarcerated them, and frequently, if not always, killed them. Finally, those deemed members of a scorned race or despised class could do very little to earn tolerance, much less security. Minimally scheduled for abuse, many, if not most, were ultimately consigned to martyrdom.

In the twentieth century, hundreds of millions of human beings suffered unnatural deaths at the hands of those who governed them. Of course, mass murder has not been unique in history, but its sanction by public rationale—providing motives to rulers, and influencing the behavior of the masses—may well be. That such a rationale licenses the systematic destruction of entire groups within a community at peace, contributes to the enormity.

That such a homicidal public enterprise has behind it the persuasiveness of moral counsel, the force of law, and the power of the state, renders its enormity almost incomprehensible. In such instances, the murder of those the state is expected to protect is not random, but governed by principle, and facilitated by carefully contrived organization. Murder on such scale, supported by public endorsement, and employing public instrumentalities, must necessarily engage the overt or tacit participation of large segments of the community—so that virtually all are made complicit. In substance, in the twentieth, humanity has experienced a century in which governments have sponsored, sanctioned, and created special facilities for the mass destruction of innocent lives. It has engaged almost everyone in the doing. All of which makes the mass murders of the twentieth century perhaps unique in history.”

• Totalitarianism and Political Religion An Intellectual History, 2012 by A. James Gregor

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"The sacralization of politics became an essential aspect of all the communist regimes that arose during the Cold War and copied the Soviet model . . . . All communist regimes established a compulsory system of beliefs, myths, rituals, and symbols that exalted the primacy of the party as the sole and unchallenged depository of power. They all dogmatized their ideology as an absolute and unquestionable truth. They all glorified the socialist homeland and imposed a code of commandments that affected every aspect of existence. They all safeguarded their monopoly of power and truth through a police state and hard line ideological orthodoxy backed by constant surveillance and persecution, which enormously increased the number of human lives sacrificed." —Emilio Gentile

In a sense the concept of God is taken over to become the State (communist party). They take away private proprietary so no one is independently economically. They attack family units because the family could be what people have more loyalty than the state.

Communists destroy religion both the one that claims there is a God, because that means people are loyal to God not state and because it provides alternative point of view in regards to morality, and that is why the see religion like Christianity or Islam etc as rival in terms of institution but also because much like family it represents loyalty dilemma.

They also don't allow individual morality, and so they say morality is no more, this is because if there is sense of morality by individual than it can be used as a perspective from which to judge actions of the party and party is never wrong.

“In their propaganda today’s dictators rely for the most part on repetition, suppression and rationalization — the repetition of catchwords which they wish to be accepted as true, the suppression of facts which they wish to be ignored, the arousal and rationalization of passions which may be used in the interests of the Party or the State.

As the art and science of manipulation come to be better understood, the dictators of the future will doubtless learn to combine these techniques with the non-stop distractions which, in the West, are now threatening to drown in a sea of irrelevance the rational propaganda essential to the maintenance of individual liberty and the survival of democratic institutions.”

• Brave New World Revisited (1958) by Aldous Huxley

I think Alexander Solzhenitsyn, in his Warning to the West speech summarized communism well.

“Communism is as crude an attempt to explain society and the individual as if a surgeon were to perform his delicate operations with a meat ax. All that is subtle in human psychology and in the structure of society (which is even more complex), all of this is reduced to crude economic processes. The whole created being—man—is reduced to matter. It is characteristic that Communism is so devoid of arguments that it has none to advance against its opponents in our Communist countries. It lacks arguments and hence there is the club, the prison, the concentration camp, and insane asylums with forced confinement.”

If you though about Spanish Inquisition. There is a lot of myths around that, if you are interested read about... The Black Legend.

The Black Legend of the Spanish Inquisition refers to a historical narrative that portrays the Spanish Inquisition as an extremely brutal and oppressive institution. The term "Black Legend" was coined in the 16th century by Protestant writers who sought to discredit Catholicism and Spain's global power.

According to this legend, during its nearly 350-year existence (1478-1834), the Spanish Inquisition was responsible for countless acts of torture, persecution, and execution against Jews, Muslims, Protestants, heretics and other non-Catholic groups. It is said that thousands were burned at stake or forced into exile during this period.

However recent research has shown that while there were certainly instances of cruelty within the ranks of those carrying out these investigations it is not accurate to say they were all like this nor did they happen on such a large scale as previously thought.

In fact many historians argue that much of what we know about The Black Legend comes from propaganda spread by rival European powers seeking political advantage over Spain rather than actual evidence-based accounts.

Regardless it remains true however that for many people living under its jurisdiction at various times throughout history - particularly those who fell afoul with their religious beliefs - life could be very difficult indeed due in part because some officials took their duties too far but also because being accused alone could lead one down a path towards punishment without any real chance for defense or appeal if found guilty which made them feel powerless against authority figures wielding so much unchecked power over them.

You don't hear about America, British, Italian, French or German Inquisition, but by the numbers they were more prolific than the Spanish one. But all them together, cannot even come close to modern governments and systems of torture, mass murder and other murderous enterprises.