The co-operative mode allows you and a friend to choose from either Rikimaru, Ayame and Tesshu. Each couple has 3 special co-op stealth kills. Stay with both chosen character close to an enemy before pressing the attack button to perform them.
As you progress further in the story mode more co-operative missions will be come available, until you have unlocked all six.
Regardless of which character or location you choose you start with the same amount of items; 4 shuriken/crimson blades. Other items may be obtainable during the level.
Village (Retrieve all 6 scrolls – 10 minutes)
Unlocked from start. Retrieve all of the scrolls that are hidden in the village. The guards are after the scrolls too. Defeat the guards who already have a scroll in their possession.
Unlock by completing first 2 missions on either Rikimaru’s or Ayame’s storyline. Lord Gohda has been wounded on the battlefield. He wont survive another hit. Guard Gohda and escort him to the safe area.
Castle (Eliminate – Stealth Required)
Unlock by completing first 4 missions on either Rikimaru’s or Ayame’s storyline. Stealth kill all enemies. Do not alert guards. Infiltrate the castle and kill everyone quickly. To be seen is to die.
Cavern (Stealth Kill Technique Test)
Unlock by completing first 6 missions on either Rikimaru’s or Ayame’s storyline. It is time for the ninja test. Earn points by killing enemies. You need 240 points to pass. Simultaneous stealth kills earn extra points. But first, you must drink this poison.
Fortress Of Evil A (Eliminate – 6 minutes)
Unlock by completing first 8 missions on either Rikimaru’s or Ayame’s storyline. The enemy is preparing to attack Lord Gohda’s castle. Exterminate all enemies as quickly as possible.
Fortress Of Evil B (Boss Arena)
Unlock by completing all missions on either Rikimaru’s or Ayame’s storyline. Use your ninja abilities to defeat all of the bosses.