When on the rooftops in stage 9-1, start smashing the many crates to find an artifact. Take that artifact back home, and give it to April. Once she appraises it, she'll tell you that it is the original TMNT aracde game. Now go to the title screen, and go under options. The original TMNT arcade game will be there.
S D S D R L D -Abyss
M R M D R M D -Challenge Code Endurance - stamina restore no longer
D S R D M R M -Cheat Code Health
L R S R D R D - Fatal Blow
R S R L R S M - Infinite Shuriken
R L M R D S L - Lose Shuriken
L S D R R D R - Mighty Turtle
D S L R D R M - New Nexus outfit for Donatello
L M R M D R D - New Nexus outfit for Leonardo
M L M R D R M - New Nexus outfit for Michelangelo
R M S R M D R - New Nexus outfit for Raphael
S L S D R D L - Nightmare
M R L M R M R -Pizza Paradise
S R M L D D R - Playmates added to Bonus Materials
D R S L L S R - Poison
D R M S R L R - Self Recovery
M L D S R D M - Squeaking
L D R M R L M - Super Defense Power (Defense x2)
S D L S R L L - Super Offense Power (Attack x2)
R D S R M R L - Super-Tough
S S S M R D D - Toddling
