Sudden Death stage:
To unlock the Sudden Death stage for purchase, win the Robo Cup, then enter one of the laboratories on the upper floor of NeoBrain. Talk to the scientist facing the glass and defeat him.
The Underground stage:
To access a secret passage to The Underground stage, win twelve Grudge matches, then go in front of the clubhouse and defeat your shadow self to get illegal parts and the Dark Commander Mark. Then, talk to the suspicious man in the southwest house in the Bayside area.
Special Robos:
To unlock the following Robos, first complete the Great Robo Cup. Then, perform the corresponding tasks:
ROBO – HOW TO UNLOCK
AIRS – Defeat Stark twice in the grudge matches.
Carat – Beat all the Robo type Mission battles, then defeat Catoreya.
Hadoron – Beat all four Greyham Boss data and Hadoron data to unlock Hadoron and his parts.
Hiykko – Go to Team No. 1’s Clubhouse and talk to the boxes above the stairs. Defeat the kid that is hiding inside the box without having a combo over 380 damage.
Meijel, Nanase set and key to the Underground – Defeat your shadow self aboveground.
Minstrel – Defeat Hajime in your classroom after he brings Saki to school.
Ray and Sagittarius Gun – Defeat Saki in your classroom after she returns.
Ray MK II – Go to your father and older sister’s lab and talk to your father.
Ray II Dark Robo – Defeat your shadow self in the underground for the second time.
X-Ray – Go to the police station, and talk to the person behind the back desk without a microwave to purchase the Robo for $500 credits.
King’s Throne