Custom Robo

Get new Robo parts and unlock Dark Core stage (japanese version only)
Connect to Custom Robo GX by using a GBA link cable

Arcade mode, 1st person view, parts index, Grand Battle in one player + VS mode:
Finish "A New Journey" mode in single player to get access to the completion
bonuses.

Unlock VS battle CPUs
Finish the game in story mode

Unlock Dark Star VS mode stage
Play in versus mode at least 50 times with any one Robo (example Ray01)

Unlock New stage
Play three matches in versus mode. Win the three matches to get access new stage.

Change stage appearance
Choose versus mode, then highlight No Man's Land or Basic Arena
then push Z button to alter the graphics of the stages.

1st person view
To unlock first person mode, beat Rahu 3 at the end of the game in story mode.
To switch between the views by using C-stick Up and C-stick Down.

Ray Legend:
Earn a gold trophy in all cups in the Z headquarters, after speak with Oboro.

Ray Warrior:
Earn a gold trophy in all cups in the Amusement Park, after speak with the
policeman. The policeman standing at the front gate.

Get the X Laser (illegal part):
Go to Bogey's Cafe in a Grand Battle mode. Look behind the counter and select
the shelf to find the X laser.

Get the Wave Laser (illegal part):
Go to the Lab Handicap battle, then hit the A button against the books.

Chickenheart:
Look on the north side of the west pillar, in the Z Boss battle.

Crystal Strike gun:
Beat the 4th CPU in the Test Center. Start talking to it until you get the
Crystal Strike gun.

Rahu III
In the outside world go to the carnival and choose Silver Battle Royal. Don't
skip the scenario then go find a broken carrige and enter it then keep
pressing A. Next visit a parts generator and you'll have Rahu III's part.,