Play as Gargos:

When you turn the game on, wait for the demo to show one of the characters biographies (where you see the vital statistics and character storyline). When this appears, press Z, A, R, Z, A, B. You will hear a laugh if you have entered the code correctly. Now Gargos is a playable character in all modes except training and focused training.

Bonus options and Special colors:

As above, wait for the demo to show one of the characters biographies. When it appears pressZ, B, A, Z, A, L. If you hear someone say "Welcome" then you have entered the code correctly.

Sky Stage:

In two-player mode, have both players select their fighters by holding DOWN and C Down.