Aero the Acro-Bat 2

Invincibility:
Press Left(2), A, B, C, Left, Up, Down, A, Right, A at the title screen.

Level select:
Enter the "Options" menu and play music 10, 15, 6, and 8 in that order. Aero will say "Yipeee!" to confirm correct code entry. Begin game play, pause, then hold Down + L + R + A to display the level select screen.

Level

Password

Boardin' Zone

Batasha, Aero, Aero, Zero

Fort Redstar

Zero, Zero, Batasha, Alter Aero

Disco Fever

Aero, Dr.Dis, Zero, Batasha

Dr. Dis Industries

Alter Aero, Batasha, Dr.Dis, Zero

Performer's Dungeon

Dr.Dis, Ektor, Zero, Aero

Ektor's Engine

Ektor, Alter Aero, Dr.Dis, Batasha