Amuro Ray:
Finish the EFF campaign on very hard difficulty setting and load the 
clear saved data.

Char Aznable:
Finish the Zeon campaign on very hard difficulty setting and load the 
clear saved data.

Fraw Bow:
Finish any campaign on very hard difficulty setting and load the 
clear saved data.

Gundam:
Obtain the rank of Warrant General.

Kai Shiden:
Finish any campaign on very hard difficulty setting and load the 
clear saved data.

Kampfer:
Get the rank of "Lt. Colonel" in the Zeon campaign. 

Kampfer (alternate):
Play the Eff campaign on very hard setting when you are Lt. General. 
It will arrive in December. 

RX-78-2 Gundam:
Reach the Colonel in the Federation campaign. 

Xamel:
Play the Eff campaign on very hard setting when you are Lt. General. 
It will arrive in December. 

Unlock Hildolfr:
Become Brigadier General and play on very hard setting in early december 
before the unidentified enemy mission you will unlock Hildolfr. 

Unlock Gelgoog:
Become Bridadier General and play on very hard setting just after you
get the Hildolfr you will unlock the Gelgoog.