Backyard Soccer [cheats] Play as Mr. Clanky:
Win the Astonishingly Shiny Cup Of All Cups. Then hold [Shift] and click on Mr. Clanky. Go to the pick up window to play as him.
All levels won:
Kick the ball out of bounds, then press [Shift] + [Tab] + [Enter].
Skip opening sequence:
Press [Esc] to skip through the opening sequence.