Insomniac referred to it as "the boat level," because it's more or less an on-rails (on-river?) section played on a boat in the early part of the game. Protagonist Joe Capelli will be making his way from Haven, Oklahoma to New York City, and early on he jumps into a boat and starts touring up the muddy Mississippi towards St. Louis, through the flooded town of Wrightsburg, Missouri.
Lead Designer Drew Murray referred to Resistance 3 as a "buddy road trip movie" a few times throughout the day, and this boat level was designed to give off the impression in a strong way early on, so as you float around trying to dodge the Chimera invasion, Capelli comes across lots of road trip imagery -- a sunken high school football field, an old submerged mill, and even a "Welcome to Wrightsburg" sign half-buried in mud and silt. By the time you float into a beat-up old motel, the Chimera forces in the area have started to notice you, and they begin to jump towards you and onto the boat, requiring Capelli to fight back while riding along.
Resistance 3's full arsenal hasn't been fully revealed, but the demo showed off both old and new weapons to the series; used in old and new ways. The Rossmore shotgun returns, but this time has a secondary fire that shoots a concussive grenade, adding a little more long-range capability. Weapons can also be upgraded as they're used more, adding explosive rounds or different abilities to the various firing modes. "All of them have primary and secondary fire, and they each have two upgrades," Murray said, so Insomniac is providing plenty of tools for Chimeran destruction.
When the goliath and its attendant soldiers finally realize where you're at, the chase begins, and the rest of the level is mostly madness, with your boat desperately trying to outrun the Chimera while you shoot and fire as best you can. Soon after, another massive goliath appears, hits the boat square on, and Capelli falls into the murky water as the demo ends.
Like the very opening battle of the game (with the brawler Chimera), the boat level seems to do a great job of "setting the tone for you in this world," as Murray says. "It's dangerous, you're vastly outnumbered, and there's never an opportunity to feel safe."