Level up: add a joystick to move the eyes…or if you’re really committed, use a webcam or a Kinect sensor on a PC (connecting to the Arduino through USB) to make the eyes automatically follow victims around the room.
Lesson learned: at 200 milliamps each, these displays get warm enough to soften the glue. Nothing fell off, but it’s something to keep in mind. If the situation permits, use the matrix backpacks’ mounting holes (obviously this won’t work with the glass head).
Level up: have the mouth move in sync with the wearer’s own…perhaps a pressure or flex sensor under the chin, or using a microphone based on volume.