Level select:
Hold L and press A, B, A, X, A, Y, A(2), B, A, X(2), A, Y, A at the prison selection screen.

Bonus level:
Hold L and press A(3), B, A, X(3), B, A, X(2), Y at the prison selection screen.

Doctor:
Hold L and press A(2), B, Y, X, B, Y, A, X, B(2), X at the character selection screen in single player mode.

Display version number:
Hold L and press A(3), B, Y, A(3), Y, X at the main menu.