Note: This game is also titled Gekitou! Custom Robo.Sudden Death stage
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 to unlock the Sudden Death stage for purchase.The Underground stage
Win approximately 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 to access a secret passage to The Underground.Special Robos
Successfully complete the Great Robo Cup. Then, complete one of the following tasks to unlock the corresponding Robo:
AIRS: Defeat Stark twice in the grudge matches. The first time he will use his regular Robo, then he will use AIRS. You can find AIRS' parts in the Underground Shop.
Carat: Successfully complete all the Robo type Mission battles, then defeat Catoreya.
Hadoron: Successfully complete 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 buy the Robo for $500 credits.
Reach "King" rank, then talk to Lambda Halburn at Neobrain.Victory diorama
Reach "King" rank, then talk to Lambda Halburn at Neobrain.Shrinking parts
At the end of the game, after purchasing the Pipit Robo, the Jameson Robo, and all Amun parts, equip the Amun parts to Jameson, then Pipit, then Jameson again. The Amun gun and Amun bomb parts will now have shrunk to the size of a normal gun, instead of giant.