Batman Beyond: Return of The Joker

N64

Level Skip:
Level 2-C76564J
Level 3-L88R8TC
Level 4-Y539WZG
Level 5-NTTJ9KY 

Original Batman Suit:
Pause the game then hold the L button while pushing C-Left, Down, Up, C-Right.
The screen will shake if down correct.

Flight Mode:
Pause the game and press Up, Down, Left, Left.

Thanks to Revolution reader Cornbread!