Here is the full list of all 57 Star Wars Knights of the Old Republic II: The Sith Lords achievements.
Break Hanharr's spirit
Reduce a companion's Influence to zero.
Acquire all Dark Side Powers.
Acquire all Light Side Powers
Deduce G0-T0's identity
Change your mind about siding with the Settlers at Khoonda
Reach Player Level 30
Convince the "champ" to lose the game without playing.
Have your character replace any of the Sith Lords on the main menu screen.
Learn how to kill Jedi from HK-47
Complete the game on the Dark Side
Install HK-47's unique module
Kill all the Jedi masters
Claim Darth Nihilus' mask.
Listen to HK-47's definition of love.
Have 30 points in Stealth
Have 30 points in Demolitions.
Have 30 points in Treat Injury.
Convince Vogga the Hutt to sell fuel to Telos.
Teach the Handmaiden the ways of the Force.
Side with Vaklu on Onderon
Learn Moving Meditation
Recruit Hanharr
Have 30 points in Repair.
Get this by starting the "Trapped" Quest on Korriban.
Complete the Handmaiden Battle Circle
Beat the champ on Nar Shadaa
Reach maximum Dark Side points
Dance for Vogga
Have 30 points in Computer Use.
Defeat Nihilus
Defeat Sion
Complete the game on the Light Side
Learn Force Sight
Recruit the Disciple
Get your first Dark Side points
Side with the Queen on Onderon
Complete the Mandalorian Battle Circle
Get the named Lightsaber crystal
Fill the Party Selection screen
Recruit Mira
Loot a body on Korriban
Side with the Settlers at Khoonda
Reach maximum Light Side points
Have Persuasion over 30
Contruct your first Lightsaber
Repair the damaged droid on the Ebon Hawk
Flee Korriban after fighting Sion
Recruit the Handmaiden
Gain a Prestige class
Win a Pazaak game with a full board
Collect 10,000 credits
Let the Sith destroy the Peragus Asteroids
Destroy Peragus Astroids
Kill all Sith troopers before they can board the Ebon Hawk
Get your first Light Side points
Complete the Prologue