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