Clear every mission in the 1-player story with a character to unlock that character's personal custom weapon. You can get a weapon for every character in the game, and any weapon you unlock can be then used by the other characters as well.

• Unlock extra weapons

When an enemy drops a weapon that you don't have in your inventory, pick it up, and make sure to finish the level while still holding it. When you start a new level the weapon will be permanently added to your inventory.

• Unlock Tachikoma minigame and Movie Viewer

Just beat the game with any character in order to unlock a SpyHunter like minigame featuring Tachikoma, and a Movie Viewer that let's you watch all of the game's cutscenes again.

While playing through a level, look for a yellow/orange box-shaped robot carrying a red and white fan. If you kill him, you will be rewarded with a special Tachikoma part when you complete the level. If it was the correct robot, you will see a "Tachikoma Part Obtained" message appear once it has been killed.

• Unlock Various Dual Handguns

If you start a mission with only a handgun equipped, at the end of the mission you will be rewarded with that same handgun in its dual form - 2 of the same gun that can be equipped at once, only needing 1 weapon slot to hold. You can use this method to unlock a dual version of each of the standard handguns in the game.

Collect a weapon that is not in your inventory during the game, then have it equipped when completing the level. When the next level begins, it will be a part of your available inventory.

Successfully complete all Single Player mode levels with a character to unlock his or her custom weapon. After unlocking it, the weapon can be used by any character.