Successfully complete the game, including the three extra missions, to unlock the "Bonus" option at the main menu. The bonus menu allows the following scenes to be viewed: "Charlie Bucket", "The Wonka Factory", "Wonkabot Troubles", "Violet Beauregarde", "Veruca Salt", "Mike Teavee", "The Special Prize", "Up and Out", "Film Trailer 1", "Film Trailer 2", and "Film Images".
To use the Candipult, press Y when near one of them. Rotate them with the Analog-stick and press Y again to set it. Aim all the candy balls into the giant bowl to complete the level.
Get two Oompa-Loompas, then find the stairs; you will find some machines. Order the Oompa-Loompas to work, then Augustus should blow up into the tube.