The Final Fantasy XV: Episode Duscae demo included with early copies of Final Fantasy Type-0 HD is named after the region Duscae, which features a lot of vast greenland and natural land formations. The part you’ll be able to explore in Episode Duscae is only part of the region, which itself is part of a bigger world more than 10 times bigger than the Duscae region itself.
There is a reason you’re stuck in the Duscae region in the demo. Your car is broken, because one certain blonde guy (ahem, Prompto) broke your car. So for the mechanic Cindy to fix your car, you’ll need to get money, which is the objective of the demo. You can figure out how to get the money yourself, but the demo’s main quest is to defeat the Behemoth, a creature wanted for a huge sum of money. If you take on the Behemoth quest, the first thing you’ll need to do is look for it by spotting footprints and such. But you’ll also get many other quests.
When it’s nighttime, many dangerous creatures will come out. So you can choose to camp (which auto-saves the game) in order to avoid them. When you camp, Ignis will cook for you and give you buffs. Buffs in Episode Duscae include:
Fresh – Slightly increases attack, defense, and EXP gained.
Prime – Greatly increases attack, defense, and EXP gained.
Sharp – Increases critical hit rate.
Immune – Negates status ailments.
In Episode Duscae, the food cooked is chosen by Ignis, but in the full game, players will get to choose what’s made.
Here is the official fact sheet outline of Episode Duscae, via Square Enix:
When you’ve spent your entire life looking out at the serrated city skyline, it’s easy to lose yourself in the sprawling Duscaen landscape. The prince and his retinue were halfway to Cauthess when their daydreams came to a sudden, screeching halt—the Regalia’s last gasp before giving out to the unpaved backroads.
Now they were truly lost in the landscape: broken down by the side of the road with the Disc well out of walking distance. The Archaean, Titan, would have to wait. He’d been dormant for ages anyway. The first order of business was getting back on four wheels.
A New Generation of Final Fantasy: The latest platform technology brings Duscae to life, rendering fast-paced action against breathtaking backdrops under a sky that changes in real time.
Open World Exploration: Guide Noctis and his entourage over the plains, through the woods, into the dungeons and around the outposts of Duscae as players roam freely about the expansive region.
Action-Packed Combat: Final Fantasy XV is the first Final Fantasy flagship title to give players direct
control over combat in real-time, resulting in an exhilarating action RPG experience.
Summoning: Uncover the astral power that will enable Noctis to call larger-than-life vengeance down from the heavens.
Engaging Quests: Adventures great and small await in Duscae.
English and Japanese Voice-Over: Enjoy English or Japanese audio with English, French, German, Italian, Japanese or Spanish text.