To get HYDRA gundam you must beat the game on hard difficulty without dieing and continuing.
Submitted by Matt Anderson
Beat it on hard in under ten minutes
Submitted by Travis Wilson
On vs. mode hit start and the x button at the same time and the gundam will be a different color
Submitted by wallas wilson
Go ro versus mode. Use the alternate colors code. Then choose Qubele.(note the opponent or second player might get the alternate colors)
Submitted by Patrick Ness