Fight As Epyon
Select "Versus" or "Trial" mode. Highlight Tallgeese and press L x4, R x4, L, R, L, R, L, R, L, R at the character screen.

Wing And Wing Zero's Super Attack
Wing and wing zero's super attack down, back, down, back + attack button.

Special
Press Down, Forward, Down, Forward, + Attack.

Wing Zero Transformation
First highlights Wing Zero and press L, L, R, R, R, R, L, R, R, L, L, L, R. This will transformed your gundam into Wing Zero in Endless Waltz.