TechLookz

Differnt outfits:
Complete the game under Normal difficulty.

Army costume:
Complete all 50 missions under Hard difficulty and achieve Ninja 5 rank.

Lion Costume, Hotdog, and Kite and Flag Costumes:
Slay 50 Tomikichi to get the Special Costumes.

Lurk and Feet:
Acquire 1,000 Stealth Kills.

Victory:
After finishing a mission press and hold Up, Down, Left, or Right right before
the "Mission Completed" screen displays to do one of 4 different
victory poses.

Xbox Live Gamerscore:

50 Missions - 50:
Complete 50 missions.

40 Missions - 40:
Complete 40 missions.

30 Missions - 30:
Complete 30 missions.?

20 Missions - 30:
Complete 20 missions.?

10 Missions - 20:
Complete 10 missions.

5 Missions - 20:
Complete 5 missions.

Ninja 5 - 40:
Complete all normal missions and reach Ninja 5 rank.

Game Story - 50:
Complete Story mode.

Hard Missions (Ninja 5) - 50:
Complete all hard missions and reach Ninja 5 rank.

Easy Missions (Ninja 5) - 30:
Complete all easy missions and reach Ninja 5 rank.

700 Stealth Deaths - 40:
Defeat 700 foes with Stealth Kills.

500 Stealth Deaths - 30:
Defeat 500 foes with Stealth Kills.

300 Stealth Deaths - 30:
Defeat 300 foes with Stealth Kills.

1000 Stealth Deaths - 50:
Defeat 1,000 foes with Stealth Kills.

50 Stealth Deahts - 20:
Defeat 50 foes with Stealth Kills.

50 Ninja 5 ranks - 30:
Complete 50 missions with Ninja 5 rank.

30 Ninja 5 ranks - 20:
Complete 30 missions with Ninja 5 rank.

20 Stealth Deaths - 20:
Defeat 20 foes with Stealth Kills.

10 Ninja 5 ranks - 20:
Complete 10 missions with Ninja 5 rank.

100 Stealth Deaths - 30:
Defeat 100 foes with Stealth Kills.