There's a speaker view. It includes a timer, preview of the upcoming slide as well as your speaker notes.
Press the S key to try it out.
Press B or . on your keyboard to pause the presentation. This is helpful when you're on stage and want to take distracting slides off the screen.
Press ESC to enter the slide overview.
Hold down alt and click on any element to zoom in on it. Alt + click anywhere to zoom back out.