Space bar toggles play/pause.
Right and Left Arrow keys seek the video forwards and back.
Up and Down Arrow keys increase and decrease the volume.
M key toggles mute/unmute.
F key toggles fullscreen off and on.
Double-clicking with the mouse toggles fullscreen off and on.
Number keys from 0-9 skip to a percentage of the video. 0 is 0% and 9 is 90%.