The short answer
The Expanded Demo is a curated pre-release build, not the opening hours of the final game. Capcom says it differs from the full game in some respects, and Demo progress cannot continue into the released game.
What the Expanded Demo adds
Capcom’s August 25 Steam update confirms a new location, more Genma combat, and a boss encounter that follows Sasaki Ganryu. These additions make the Demo a broader combat sample, but they do not establish the final game’s route order or progression structure.
What carries into the full game
Story and gameplay progress do not carry over. Qualifying Demo save data is instead used to grant the Kubi Akari reward in the full game. Keep the save data if you want the bonus; do not expect a Continue option to resume the Demo route.
What the Demo does not show
The Demo does not reveal the complete boss order, build progression, skill tree, weapon locations, puzzles, collectibles, maps, or quests. It cannot establish final-game balance or completion requirements. Use the Demo guides for practice, not as full-game walkthroughs.