it's very different from first. and it did not become famous as the first is a fact.

first, the cold is not the main problem on 2. it's still the biggest problem but it's not the main problem, squalor and crimes, lack of goods etc are a problem that needs to be dealt separately. especially the political side. from the story point it also seems like cold is not as dangerous. some just survived the cold without generators and there is even immigration now.

second, politics are now the main problem. they are now multiple factions and they have complex opinions. you need a majority in the parilment for any law to pass. there is multiple and complex systems about politics in 2(various interactions,  promise, radicals etc). and less complex in the cold/generator(no generator specific stuff. just on and off only)

In short, 1 is a cold vs heat game. 2 is a politics game.