Killer7's gameplay is probably one of the most-complained about flaws, but it's there for what it represents, not for how enjoyable it is. As Hardcore Gaming 101 pointed out, Americans love freedom. That's why they formed their own nation, and that's why they prefer cars to public transport; cars can go on any road, while public transport follows predetermined routes, and you only occasionally need to change direction to get to your destination. However, in Japan, people use public transport all the time, and cars aren't a central part of the lifestyle. This is also reflected in Role Playing Games: while America makes open-world RPGs, Japan makes linear story-driven RPGs. A major theme of the game is how cultures often try to force themselves onto each other, so the gameplay serves as a reverse of the storyline - rather than America forcing democracy onto Japan and Japan wanting to nuke them in revenge, Japan forces linear paths onto Americans and Americans get pissed off about it. Kind of like how people got annoyed by Liquid possessing Ocelot in Metal Gear Solid 2: they both represented a villain for Snake to defeat, but possession didn't really make sense in the context of the MGS universe.
The title of the first chapter (after the prologue) is SUNSET. It describes the potential destruction of Japan, the Land of the Rising Sun.