What happens at midnight?
Once the investigation takes you into Mount Hillthorn, the announced full-game rules change: the day restarts at midnight. You progress by using what you have learned on earlier attempts.
You are not expected to solve the entire mystery through fast inputs in a single real-time session. Hillthorn has no quick-time events or real-time input challenges. Actions consuming in-game time are a separate mechanic from how quickly you move the mouse.
The pocket watch
The pocket watch lets you move time forward to wait for an event. The opening meeting with Abigail is one example of a time-dependent appointment.
Use the watch when you want to reach a particular moment rather than assuming every action must be performed immediately.
Does the Demo include the complete loop?
The October 22 update says that the complete time loop is not part of the Demo. Treat the full-game reset as an upcoming mechanic, rather than expecting the trial to show every part of it.
Which cards or objects survive a reset has not been specified. Avoid planning around an assumed inventory reset rule before playing the full release.