At the "press start" screen, keep wiggling the joystick to stop the rolling demo kicking in. When a bug or something passes by, use the C stick to control it. If you get a Bulbax, use the Z button to eat pikmin, they do get eaten, and you see them missing in the "pikmin" text when they join up later. Press the R button to scatter the pikmin, or dismiss the creature you are controlling. Yes I was bored...
Yeah sort of, if you get one of those big beetles, you can move it and make the pikmin swarm around you, or as a bulbax, eat them. I gave up after a while, so im not sure if there are other creatures to control.