Complete the following tasks to unlock the corresponding gamerscore.

Mission 5 Cleared - GamerScore 20:
Clear up to mission 5.

Mission 10 Cleared - GamerScore 20:
Clear up to mission 10.

1 Secret Mission Cleared - GamerScore 20:
Clear 1 secret mission.

10 Ninja 5 Ranks - GamerScore 20:
With Ninja 5 Rank complete 10 missions.

30 Ninja 5 Ranks - GamerScore 20:
With Ninja 5 Rank complete 30 missions.

2 Secret Missions Cleared - GamerScore 20:
Clear 2 secret missions.

20 Stealth Kills - GamerScore 20:
With Stealth Kills defeat 20 enemies.

50 Stealth Kills - GamerScore 20:
With Stealth Kills defeat 50 enemies.

Killed 5 Tomikichi - GamerScore 20:
Kill 5 Tomikichi.

Killed 10 Tomikichi - GamerScore 20:
Kill 10 Tomikichi.

Killed 20 Tomikichi - GamerScore 30:
Kill 20 Tomikichi.

Killed 30 Tomikichi - GamerScore 30:
Kill 30 Tomikichi.

Ninja 5 All Easy Missions - GamerScore 30:
With Ninja 5 rank complete ALL Easy missions.

100 Stealth Kills - GamerScore 30:
With Stealth Kills defeat 100 enemies.

50 Ninja 5 Ranks - GamerScore 30:
With Ninja 5 Rank complete 50 missions.

500 Stealth Kills - GamerScore 30:
With Stealth Kills defeat 500 enemies.

3 Secret Missions Cleared - GamerScore 30:
Clear 3 secret missions.

Mission 20 Cleared - GamerScore 30:
Clear up to mission 20.

Mission 30 Cleared - GamerScore 30:
Clear up to mission 30.

300 Stealth Kills - GamerScore 30:
Defeat 300 enemies with Stealth Kills.

4 Secret Missions Cleared - GamerScore 40:
Clear 4 secret missions.

700 Stealth Kills - GamerScore 40:
With Stealth Kills defeat 700 enemies.

Killed 40 Tomikichi - GamerScore 40:
Kill 40 Tomikichi.

Mission 40 Cleared - GamerScore 40:
Clear up to mission 40.

Ninja 5 All Normal Missions - GamerScore 40:
With Ninja 5 Rank complete ALL Normal missions.

1000 Stealth Kills - GamerScore 50:
With Stealth Kills defeat 1000 enemies.

5 Secret Missions Cleared - GamerScore 50:
Clear 5 secret missions.

Cleared Story - GamerScore 50:
Clear the story.

Killed 50 Tomikichi - GamerScore 50:
Kill 50 Tomikichi.

Mission 50 Cleared - GamerScore 50:
Clear up to mission 50.

Ninja 5 All Hard Missions - GamerScore 50:
With Ninja 5 Rank complete ALL Hard missions.

Unlock Special Costumes:
Eliminate 50 Tomikichi.

Unlock the Modern Army Costume:
Beat ALL 50 missions with Ninja 5 ratings.

Unlock Lurk and Feet Abilities:
Perform 1,000 Stealth Kills to unlock the two abilities at the end of the mission you are currently doing.