Beating the game unlocks the event viewer and mission mode. Shoot or break memory capsules in mission mode to unlock character art, soundtracks, and more missions.
Collect all three G reports.
Extra hard difficulty:
Beat the game on normal or hard difficulty
Extra hard + difficulty:
Beat the game on Extra Hard difficulty.
Get up faster:
If you get knocked down, wail on Square to get up faster.
In chapter 3, you can find an item called the Toy Gun. You'll be able to upgrade it like your other parts. It's next forms are the Silver and Gold Toy Guns, but it's final upgrade is the Omega Weapon which costs 200,000 gil.
Thanks to Revolution Reader Man-Bot!