At the level selection screen, hold L + R to display the code entry screen. Then, use the D-pad to enter one of the following codes. Press X to accept and activate the code.

Level select

Enter "LVLANY1" as a code.

Disable level select

Enter "LVLANY0" as a code.

Invincibility

Enter "INVINC1" as a code.

Disable invincibility

Enter "INVINC0" as a code.