Complete the following achievements to unlock Xbox Live Gamerscore points.

Cloak & Daggers (10 points): Deal with the man in the shadows.
Smash the State (10 points): Help Officer Nicholas take out the trash.
Acquaintances Forgotten (10 points): Follow Pritchard's lead to uncover the truth.
Doctorate (50 points): Read all 29 unique XP books within a single playthrough.
Lesser Evil (10 points): Deal with Mr. Carella's indiscretion.
Motherly Ties (10 points): Put a grieving mother's doubts to rest.
Corporate Warfare (10 points): Protect a client's interests by performing a less-than-hostile takeover.
Talion A.D. (10 points): Descend into the bowels of an urban jungle and confront a warrior-priest.
Gun Nut (20 points): Fully upgrade one of your weapons.
Bar Tab (10 points): Help the Hive Bartender settle a tab.
Rotten Business (10 points): Help a lady in the oldest of professions clean house.
Shanghai Justice (10 points): It may take some sleuthing, but justice must be served.
Hax0r1! (15 points): Successfully hack 50 devices within the same playthrough.
Transhumanist (5 points): Fully upgrade your first augmentation of choice.
Consciousness is Over-rated (15 points): Knock out 100 enemies in a single playthrough.
First Takedown (5 points): Perform your first Takedown. Civilians don't count, so be nice.
Opportunist (15 points): Perform 50 takedowns within the same playthrough. (Civilians don't count.).
First Hack (5 points): Perform your first Hack successfully.
Deus Ex Machina (50 points): Experience all the different endings that Deus Ex: Human Revolution has to offer.
Pacifist (100 points): Complete Deus Ex: Human Revolution without anyone dying by your hand. (Boss fights don't count.).
Foxiest of the Hounds (100 points): Complete Deus Ex: Human Revolution without setting off any alarms.
Up the Ante! (15 points): Upgrade your first weapon of choice.
Trooper (50 points): Complete Deus Ex: Human Revolution.
Legend (100 points): Complete Deus Ex: Human Revolution at its hardest setting without ever changing the difficulty.

Additionally there are twenty five secret achievements.

Ghost (15 points): You made it through an entire hostile area without so much as a squeak.
Sentimental Value (10 points): You kept Megan's bracelet for yourself. Apparently, letting go really is the hardest part.
The Take (10 points): Greedy ***. You accepted O'Malley's blood money and let him go.
Guardian Angel (10 points): You paid poor Jaya's debt in full. How very.. humane.. of you.
The D Project (15 points): You watched the entire credit list and saw the surprise at the end.
Good Soul (15 points): Against all odds, you saved Faridah Malik's life.
Hangar 18 (10 points): You found and read the secret message. Now you know too much..
Super Sleuth (10 points): You really nailed your case against Lee Hong.
Ladies Man (10 points): You convinced Mengyao to spill the beans on the mysterious Hyron Project.
Balls (5 points): Seems you like playing with balls, eh?
Lucky Guess (10 points): Next time, Jacob better use a more complex code to arm his bombs.
Kevorkian Complex (10 points): You granted a dying man his final request.
The Fall (10 points): You sent Diamond Chan on the trip of a lifetime.
The End (25 points): You defeated Zhao Yun Ru and destroyed the Hyron Project.
Old School Gamer (10 points): You found all the hidden story items in Megan's office. Point and Click much?
Unforeseen Consequence (15 points): You convinced Zeke Sanders to let his hostage go.
The Bull (25 points): You defeated Lawrence Barrett, elite member of a secret mercenary hit squad.
The Mantis (25 points): You defeated Yelena Fedorova, elite member of a secret mercenary hit squad.
The Snake (25 points): You defeated Jaron Namir, Leader of Belltower's Elite Special Operations Unit.
The Throwdown (15 points): You convinced the smooth-talking politician Bill Taggart to tell the truth in public.
The Last Straw (15 points): You talked Doctor Isaias Sandoval out of suicide.
The Final Countdown (15 points): You showed millionaire Hugh Darrow that his logic was flawed.
The Desk Job (15 points): You convinced Wayne Haas to let you into the morgue.
Yes Boss (15 points): You had an argument with your boss, David Sarif, and won.
Darker Shades (15 points): You convinced a fast-talking bartender to let you see Tong Si Hung.