At the 'Options' menu in Gru's Lab enter the following codes to unlock the corresponding effect.
Unlock Village Folk Costume: Enter Triangle, X, X, Circle, X. The costume can be select at the 'Bonus Content' option at the 'Hub' screen.
Unlock Minionettes Costume: Enter Circle, Circle, Square, Triangle, X. The costume can be select at the 'Bonus Content' option at the 'Hub' screen.
Unlock Taffy Web Gun: Enter X, Circle, Square, X, Triangle. When this code has been enabled the Web Gun in Gru's hand will be replaced with a pink version and the HUD icon for the Web Gun is replaced with a pink version. The Web Gun effects on ALL objects, enemies, and Minions as well as the Web stream/shot itself are pink instead of white.