To get Big Zam
Finish easy mode
To get Neuziel
Finish normal mode
To get Psycho mk 3
Finish hard mode
Press Down,Forward,Down,Forward + Punch
To get HYDRA gundam you must beat the game on hard difficulty without dieing and continuing.
Beat it on hard in under ten minutes
Different Colored Gundams
On vs. mode hit start and the x button at the same time and the gundam will be a different color
Beat Game with Quin Mantha after you get Big Zam and Nei Zuel
Get Qubele Mark 2
Go ro versus mode. Use the alternate colors code. Then choose Qubele.(note the opponent or second player might get the alternate colors)
Get Char's Zaku II
While on the main screen highlight options and press: left, up, right, down, square, triangle, circle. You will hear a noise that confirms you have put in the code correctly. (he is only selectable in V.S. mode)
General Anazable Zaku Gundam
To get this mobile suit you must press left,up, right, down, square, triangle, circle after you hear the person say gundam battle assualt. You should hear a noise if you did this correctly.
Only works in versus mode. its the gundam all the way to the right.
Get Gundam RX-78
To get Gundam RX-78, you need to beat the game on any difficulty with Z-Gundam. Next beat the game on any difficulty with the Sazabi. While fighting as the Sazabi the RX-78 Gundam should appear. Beat him and finish the game. Once done the RX-78 Gundam should be selectable in the vs. mode.
Note: You may need to fight many times as the Sazabi for him to show up.