It will be possibly to deactivate the displayer. It will also be possible to deactivate the rest of the HUD so you don't know how much health/ammo you still have, like in the classic RE's.
I think Leon's stay in Tall Oaks and even his trip to China will be like this demo. However, I think it'll shift to action (dramatic horror lol) once you get to China.
Yes, they did that so you wouldn't keep dieing in the demo. not being able to finish a demo must be very demotivational...
And I think there will be various difficulty modes so harder modes will have less ammo and easier modes more ammo. The demo must be set to the easiest difficulty so you can have fun and not find it too hard.