I think I've got basic controls and operation modes, and I guess.. there isn't much more too it?

It has slow animation mode (when it has more than 1 hour set). Also indicates that HH:MM (hours over and minutes under) format is active by two rectangles to the sides.

It has fast animation mode (when less than 1 hour is left)

It has blinking animation when time is up

And here is how you set it up. You can rotate main dial for large time leaps or spin the button for more precise control. Pushing it starts the countdown, pushing it again pauses the countdown. Long press resets paused countdown back to time setup.

Time to add some buzzing action.