All Stars
Press R, Up, Down, L, X, B, Left, Right, B, A on controller two at the Title Screen.

Dogs
Press Up(2), Down(2), Left, Right, Left, Right, B, A on controller two at the Title Screen.

Extra Skill Points
Enter edit players mode before each match and use all available skill points. Highlight the “Cancel” option and press Y for 200 additional skill points.