Can somebody summarise all the ways in which this instalment differs from V2?
Kind of a tall order. I'll try to hit the big points, and also point you toward
this review since comparing the two is the main point of discussion.
-Global market is replaced by various national markets which can trade with each other
-RGOs and factories are replaced by a system of buildings, which accept various inputs and employ POPs to produce certain outputs (goods, but also things like bureaucratic capacity for your government buildings, the ability to build more buildings for your construction industry, or regiments for your army for your barracks)
-All war declarations now go through something like the V2 crisis system "Diplomatic Plays" where various powers can take sides and someone might decide to back down before matters escalate to war.
-The concept of "Westernization" is gone. Instead states like China and Japan are "Unrecognized", which is essentially simply a diplomatic penalty (recognized powers take less infamy from attacking unrecognized states I believe). You can achieve recognition through a Diplomatic Play (modeling the Russo-Japanese war essentially)
-Regions on the map which would have been empty "uncolonized territory" are now occupied by "decentralized" states. These are non-playable, but fully model POPs, and may also try to resist colonizing powers.
-Army control is completely different from other Paradox titles and is much more abstracted. No more moving little men around on a map. I haven't played with it much, but the idea is that the player's role is more "politician yelling at the generals over the phone" rather than "general directing the campaign"
-Politically conscious POPs join various interest groups which compete to control the government. Managing the happiness and relative power of the interest groups to achieve your desired configuration of laws is the main goal of the political management part of the game.
For example, many countries are dominated by Landholding Aristocrats at the start of the game (who might be 1% of the population but have a majority of the political power). Their power comes from both the economic makeup of the country and the system of laws. A common playbook for those who want to liberalize is to create a class of wealthy capitalists (wealth = power) which form a secondary powerbase and then try to gradually pass reforms to erode the power of the aristocrats- replacing feudal levies with a centrally controlled army (empowering the Army), replacing hereditary bureaucrats with those appointed by merit (empowering the Intelligentsia), and eventually ending Serfdom (which totally wrecks the power of the Aristocrats)
Overall, I'm enjoying it. The base systems seem pretty solid. Currently I think they need to do a lot of work on UX (it's hard to find the information I want), as well as adding more country and region specific content (which I imagine is going to be the main focus of the monetization model).