Unlock Mission Mode:
Complete the game.

Unlock Extra Hard Mode:
Complete the game on Normal or Hard difficulty setting.

Unlock Extra Hard + Mode:
Complete the game on the Extra Hard difficulty setting.

Unlock Ultima Weapon:
Find the 'Toy Gun' weapon which is in Chapter 3. It requires 300,000 Gil to upgrade and the first upgrade will make it a Silver Toy Gun. The second upgrade makes it a Gold Toy Gun and the final upgrade which costs 200,000 Gil will make it the Ultima Weapon.

Skip Intermission Sequences:
During an intermission sequence press 'Start' and then 'X' and the sequence will stop and the game will resume.

Once you have completed the game and have it saved somewhere, reload it and you can view various cut scenes, you'll be able to view cutscenes according to what memory capsules you have collected.

Memory Capsules:
Save the game when it is completed and load the 'Clear Game' data and you you will be able select Cut scenes. The more Memory Capsules you collected during game play the more scenes you will be able to select.

Extra Ending:
Collect 3 G Reports and complete the game to get an extra ending after 'The End'.