Add Defeated AC Emblems
To add the defeated AC's emblem to your list, press Select + Start when viewing a defeated AC at the victory screen. If done correctly, you will hear a sound.
First Person View
Insert a memory card with saved game files from Armored Core 2 or Armored Core 2: Another Age. After saving and resuming in Armored Core 3 from that memory card, pause the game, then press L1 + R2 + X + Square + D-pad to get a first person view of the current screen. Note: The screen will return to normal when the game is resumed.