When in the underground city, while facing the giant heads that you have to fight then use alchemy, destroy two then transmute a wall. Jump on top of wall. You will then be able to jump over the head.
Unlock Character Mode
Comple Story Mode.
Unlock Gallery pictures
Complete the indicated task to unlock the corresponding picture in the gallery.
Unlock Hard Mode
Complete story mode.
Unlock Picture 1-1
Complete the game eight times and select the squares at the end.
Unlock Picture 1-2
Have the Game Boy Advance game Fullmetal Alchemist: Omoide no Sonata in the cartridge slot.
Unlock Picture 1-3
Have the Game Boy Advance game Full Metal Alchemist:Hagane no Renkinjutsushi in the cartridge slot.
Unlock Picture 2-1
Complete character mode as Ed without continuing.
Unlock Picture 2-2
Complete character mode as Al without continuing.
Unlock Picture 2-3
Complete character mode as Mustang without continuing.
Unlock Picture 3-1
Complete character mode as Armstrong without continuing.
Unlock Picture 3-2
Complete character mode as Scar without continuing.
Unlock Picture 3-3
Complete character mode as Izumi without continuing.
Unlock Sound Library Voices
Successfully complete character mode to unlock that character's voice in the Sound Library.