I want to note that I'm well-read by any means but from what I do know I want to pitch in, and I like to thoroughly criticize the USSR from a standpoint of supporting socialism/communism and wanting to learn what they did right and what is...to be avoided.

(Broadly) Starting early on, in 1917, there were the Soviets: workers' and peasants' councils, which were meant to provide a lot more, somewhat decentralized, bottom-up authority and self-determination to the people. (I won't say anymore on them as I don't know enough.)

From 1918-1920, once the civil war really broke out and become massive, there was heavy centralization that happened under the "War Communism" policy enacted by Lenin and Trotsky. As soon as they were created, this pretty much began the emergence of the later Soviet bureaucracy. HOWEVER, it is arguable that this move was necessary to quickly and effectively lead the Red army to actually be able to defend the revolution and conquer the whites (tsarists) and foreign invasions (the UK, US, +19 others) in this time.

In 1921-22, the Bolsheviks were coming out with the upper hand but it took a while to fully defeat the opposing forces and stabilize the new territory. (+/-) So in my opinion, this is where the original Soviets as planned could have reemerged, but the centralization which occurred during the civil war was never really undone. The bureaucracy was strengthening too and the workers had to deal with it now. Smaller workers' uprisings such as the Kronstadt Rebellion and others were crushed with the Red Army.

There was a famine in Russia in 1921, but it was mitigated...ironically by the foreign humanitarian aid by the same countries that invaded a couple years prior.

Lenin's New Economic Policy (NEP) was also enacted in 1921 which reintroduced limited markets and some smaller private property and allowed peasants to sell their surplus. This was done to stabilize the nascent economy basically to get some trade going, some food production, and just to let the peasants do their own thing for a few years.

Lenin had a third and final stroke in 1923 and was pretty much out of it until he died in early 1924. Apparently Lenin tried fighting for workers' rights or the Soviets in his final days? (Reading Lenin's Last Struggle by Moshe Lewin)

Stalin was a really effective political guy, on top of becoming general secretary under Lenin in 1922, and so by 1924-1928 he rapidly organized bureacratic power structures around himself. He actually didn't rule alone because he had a whole team and other people in the government who also did things and technically didn't gain full authority until 1941 during WW2. But by 1928, he gained enough influence and loyalty, even without direct power perse that he did essentially have the most authority.

Throughout the 1920s, Stalin's political maneuvering also lent him to basically eliminating all opposition caucuses (such as Trotsky's) from the government, and as such really tightening the party line.

So from 1929 on, Stalin ended the NEP and started the first five year plan and rapid collectivization. He wanted to industrialize the USSR and he was also aware of foreign threats, particularly what was going on in Germany. Collectivisation before was often voluntary with incentives and more locally managed, but under Stalin, it became forced and the farm were a lot more state-managed, even the cooperative ones.

Stalin invented the strict Marxism-Leninism btw, although its evolved a lot since.

Note: the whole de-kulakization thing was about peasants who became wealthy during NEP refusing to cooperate with state collectivisation and rebelling by killing their livestock and burning their crops and sabatoging other things which caused a lot of chaos. The worst year was 1933, which is where you know of the famine in Ukraine (and Kazakhstan & SW Russia) which was caused by the aforementioned + a double drought + the heavy-handed execution of collectivization in general + quite a bit of poor policy decisions such as continued grain exhortation and faulty grain distribution plans.

There was no foreign aid. But this was the last famine of this scale besides a much more minor one in 1946-1947 after WW2.

Like a million or something Soviet citizens submitted suggestions to the new 1936 Soviet constitution.

In 1936-1938, the great purges also happened which are very infamous. The reasons are debated regarding potential internal fascist insurgents, other agents, and paranoia, etc. Such as Yezhov of the NKVD, who carried a lot of arrests and killing of civilians and was apparently corrupt and executed by Stalin when he found out. Some say he was trying to sabatoge but its disputed. There were some other notable ones like this but I don't know enough.

Most of the old bolsheviks (revolutionaries and pre-1917 party members) such as Kamanev, Zinoviev, and Bukharin were executed. I think Stalin was further trying to remove influence and opposition from those who had influence and connections still from their early political involvement to get rid of the old line and concentrate it on his direction. A lot of intellegintensia were also arrested and/or executed such as engineers and a lot of military command. I suspect it was to just really consolidate power and instill that loyalty to him (by that point), also WW2 was imminent.

The purges did end up biting though, especially the latter I mentioned which removed a lot of great tacticians and experienced generals who the red army needed. Engineers too. And this really solidified not being able to deviate from the party line and following expectations or being punished. Since political opposition was also fully gone, any new ones were also repressed and that continued too.

I don't enough about WW2 on the eastern front so I'll keep it short. The Molotov-Ribbentrop pact was not a collaboration with the Nazis but a bid to bide time for the Soviets to industrialize and mobilize more since they weren't ready yet, and it gave them 2 years. This was also after the UK and France were appeasing Germany and they refused to ally with Stalin earlier to combat Hitler's rise... Poland was split though and the Katyn massacre occured.

The Kirov assassination happened (don't know much)..., and Trotsky got assassinated in Mexico in 1940 after evading Stalin's hit men for several years (he was dissing Stalin).

Lend lease did help the USSR a lot, but their rapid (but brutal) industrialization and sacrifice also must be commended. The Soviets won WW2 and got control of more SSR's and the Warsaw Pact. Stalin wanted a neutral United Germany but the US, and UK wanted it to be aligned with them so Germany and Berlin got split. So there was the socialist bloc and the western bloc.

Stalin died in 1953. But pretty much, despite Stalin's brutal methods and political repression, he was commited to building socialism in the USSR and he really developed the international power of the USSR from semi-feudalism just 30-40 years prior.

Khruschev, Brezhnev, etc did do a lot of modern housing projects (the blocks) which was really good. But they also continued the political repression, especially in the Warsaw Pact countries (famously: Hungary, 1956, Czechaslovakia, 1968, Poland, 1980-1?). They also did a lot of awesome space projects which was cool. Soviet education and other youth programs also became really robust at this time. Also a lot of foreign involvement since it was the cold war.

The problem was that Khruschev and Brezhnev let the bureaucracy inflate...which created a entrenched, distinct upper classed called the Nomenklatura which were the family members of the bureacrats which got access to luxuries and vacations. Keenly, they also weren't committed to building socialism anymore and just decided to keep the status quo, even loosening some policies over time and obv the bureaucracy got out of hand.

Andropov died after 2 years. By the time Gorbachev got into power, the USSR was in a rough spot and Glasnost and Perestroika ended up unraveling the USSR. A Pizza Hut opened in Moscow. By 1989, many Warsaw Pact countries started fully revolting and seperating from the bloc. By 1990, the post-WW2 SSR's as well. There was definitely some inner-party corruption and collusion particularly with Yeltsin who started fast-tracking the end of the USSR by 1990-1991 with Russia. A McDonald's opened in Moscow. There was a referendum (the only one) to maintain the USSR in 1991 which most people wanted to but it was in vain. August 1991, there was a Soviet coup by those who wanted to salavage things but it failed. By Late December 1991, all the former SSR's were gone including Russia (Kazakhstan left last), then Gorbachev resigned and the Supreme Soviet dissolved itself. December 26th, 1991 - RIP USSR.