Outside of the short but extremely enjoyable campaign,
Sunset Overdrive: Dawn of the Rise of the Fallen Machines rounds the same bases that its predecessor does. There's a handful of new challenges, some of which take elements from the regular missions, as well as the requisite points, traversal, and bomb delivery challenges. There are also UFOs hovering around the map; a welcome addition, since hunting collectibles has always been a ton of fun in this game.
New implements of destruction also make their debuts, as well. The Fizzco DSRC is an extremely fun and extremely expensive orbital strike weapon that deals massive damage to targets you lock on to. Just be sure to hoard away that Overcharge; at 200,000 cans, it's a doozy. The second can be earned by completing a mission for Buck National. The Swarming Nanobots are exactly what the name implies; an orb fired from the gun explodes into a tiny cloud of death that deals damage over time. Two new traps assist in your vat defense attempts. The Laser Mortis is an automatic laser turret, and the Dark Matter Device transforms OD into friendly Fizzco Bots. Two new Amps provide new bonuses for killing with style; the Heat Sink Smash freezes divebombed enemies, and Come, Boo-Boo gives you a chance to summon the most powerful NPC in the game, the cute little robotic death-dealing canine known Boo-Boo.
Chaos Squad offerings are mostly the same, but two of them deserve special mention: one for incorporating elements from the Dawn of the Rise of the Fallen Machines campaign, and the other for reintroducing us to the foul-mouthed mascot Fizzie.