Was Cambodia the "last" communist revolution of the twentieth century in a sense? The Cambodians were in a kind of "great leap forward" of atrocities, compressing the purges and famines that had happened at different times over decades of Soviet and Chinese rule into a few years. That's applying a kind of "ur-communist or "ur-revoution" framework with a revolution/civil war followed by purges, a disastrous collectivization of agriculture, and a period of stagnation if the regime last long enough.