Pt 1 and Pt 2 aren't bad to knock out in one sitting, especially on a 2nd playthrough. However, I'm sorry to do this, but I HAVE to talk about Pt 1. There will be quite a few spoilers.
[*]Sunset Pt 1 opens up with all of the world building elements of Killer 7. International highway systems bring people and goods all over the world, while air travel and anything dealing with the word "Nuclear" is outlawed. World at peace and everything is dandy...oh, and Smiles blow shit up now. "Killer 7" are the only people that can actually kill Smiles apparently.
Garcian's contact calls leaving a message about "gaining his vote for the Republic party for this coming election", which alludes that it's a code phrase for Garcian's contact to, well, contact him. Harmon is a really old man, and damn near catatonic, that gets abused by his caretaker, Samantha, and Garcian has no issues paying for her services. When Garcian wants to talk to Harmon, it's through the TV, which transforms the room into something that only exists in a void, with Samantha playing the subservient maid, and Harmon speaking as a wise master assassin, giving orders to his padawan of sorts. It's weird how much that TV of a role that thing plays. I wonder if it gets explained in the later chapters.
Meanwhile missiles are launched straight at Japan. The US has absolutely no clue where the attack is coming from, and the game never tells us. The only thing that's important is that it's heading for Japan, and Fukushima is the middle of the whole thing. He's being backed by I think the UN party, and the goal is to convince the US to stop the attack. Apparently, from what I got out of this, is he's the architect of the Yakumo Party Policy, or Yakumo for short. So, I'm guessing his plan was to reveal the Yakumo, or use it to bribe the US into stopping the attack. As to exactly "what" the Yakumo is, this chapter doesn't go into any sort of detail about it. However, I'm not sure Tim or anyone else that has at least gotten to the "HOLY SHIT" reveal agrees with me, but I think I know EXACTLY what that policy is (but we'll have to wait until Lion, I believe).
However, and this isn't the first time I've seen stuff from Japan, this goes back to the unconditional surrender of Japan, ending WWII. Namely the agreement that Japan is not allowed to have a standing army. Period. In fact, it's only protection comes from the US and other allies. Rather, Japan's only protection is staying in good graces with the other nations. So, of course, the fate of a nation rests with assassins and backdoor politics (wouldn't be the first time...ZING!) A lot of this comes from Travis. For being a ghost, he is extremely well informed on how the current situation is panning out and how it got to there.
Right now it seems like a total shame that Mask is so much more of a bad ass in cutscenes than he is in gameplay. I never thought dual grenade launchers would be so ineffective against anything outside of a cutscene. Though he really doesn't get enough chances to HEADBUTT A FUCKING BULLET...AND WIN! Also, when Con uses his jump, the text says "The Eagle has Landed on the Roof". I keep thinking that's a "Lunar Lander" reference.