Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

MI6 Ops Recruit (10 points): Earn 10 stars in MI6 Ops.
MI6 Ops Specialist (25 points): Earn 25 stars in MI6 Ops.
MI6 Ops Elite (45 points): Earn 44 stars in MI6 Ops.
Operative (10 points): Complete all objectives for every mission on Operative difficulty.
Agent (15 points): Complete all objectives for every mission on Agent difficulty.
007 (25 points): Complete all objectives for every mission on 007 difficulty.
Classic (40 points): Complete all objectives for every mission on 007 Classic difficulty.
Arkhangelsk Dossier (40 points): Complete all objectives in Arkhangelsk on 007 difficulty or higher.
Barcelona Dossier (15 points): Complete all objectives in Barcelona on 007 difficulty or higher.
Dubai Dossier (15 points): Complete all objectives in Dubai on 007 difficulty or higher.
Severnaya Dossier (30 points): Complete all objectives in Severnaya on 007 difficulty or higher.
St. Petersburg Dossier (40 points): Complete all objectives in St. Petersburg on 007 difficulty or higher.
Nigeria Dossier (40 points): Complete all objectives in Nigeria on 007 difficulty or higher.
Phone a Friend (15 points): Get 20 kills with hacked drone guns in 'Jungle'.
Bullet Dance (20 points): Get 40 kills with the Wolfe .44 in 'Nightclub'.
Emblem Hunter (5 points): Single Player: Find and destroy a Janus emblem.
Emblem Marksman (10 points): Single Player: Find and destroy 20 Janus emblems.
Emblem Elite (15 points): Single Player: Find and destroy 50 Janus emblems.
I am INVINCIBLE! (25 points): Single Player: Complete any mission without taking any damage.
Dressed to Kill (20 points): Single Player: Complete any mission without collecting any body armor on 007 Classic difficulty.
Going Dark (15 points): Get to master engineering in 'Facility' without reinforcements getting called in.
Choppers Down (15 points): Shoot down 15 helicopters in 'Tank'.
Invisible Descent (15 points): Get to the server room in 'Bunker' without reinforcements getting called in.
Secret Servers (10 points): Destroy all the servers in 'Archives' within 40 secs of the first being damaged.
Haven't Got Nine Minutes (15 points): Complete 'Airfield' in under 4:35 (007 Classic difficulty).
Made you feel it, did he? (10 points): Single Player: Silently subdue 30 enemies.
Master at Arms (10 points): Single Player: Make a kill with every weapon.
Get to the Chopper (15 points): Complete 'Carrier' in under 11:00 (007 difficulty or higher).
Russian Escape (15 points): Complete ‘Archives’ in under 15:10 (Agent difficulty or higher).
Solar Agitated (15 points): Complete ‘Solar’ in under 13:00 (007 Classic difficulty).
Orbis Non Sufficit (15 points): Public Match: Complete a match on every map.
Butter Hook (15 points): Public Match: As Tee Hee, get the most kills with a melee strike (min 3 melee kills).
Au-ned (30 points): Public Match: Achieve 79 kills with the Golden Gun in Golden Gun mode.
Clobbering (30 points): Public Match: Achieve 64 melee kills with the KL-033 Mk2.
Hat Trick (20 points): Public Match: In one life, make three kills with Oddjob's hat.
Braced for Impact (15 points): Public Match: As Jaws, survive a shot to the head which would otherwise have killed you.
The Man Who Cannot Die (15 points): Public Match: As Baron Samedi, survive a bullet which would otherwise have killed you.
Console Compliancy (30 points): Public Match: Capture and defend the most consoles in one match of GoldenEye mode.
For England, Alec (20 points): Public Match: As Bond, kill 006 with an explosive device.
The Other Cheek (20 points): Public Match: As Bond, kill Zukovsky with a melee strike.
Full Deck (15 points): Public Match: Play at least one complete match of Classic Conflict with every character.
Boys with Toys (50 points): Public Match: Kill 50 enemies with Proximity Mines.
Lucky Seven (40 points): Public Match: Defuse a planted bomb which has exactly 0:07 seconds remaining on its fuse.
Boxing Clever (30 points): Public Match: Earn all accolades specific to Black Box.
Had Your Six (30 points): Public Match: Kill six enemies with the Wolfe .44 or Gold Plated Revolver without reloading.

Additionally, there are five secret achievements:

Rocket Man (15 points): Kill an enemy with the RPG in 'Dam'.
Royal Flush (2 points): In 'Facility', successfully kill the enemy in the toilet cubicle without any shots being fired.
Dance Commander (5 points): Surrender to the music in 'Nightclub'.
Welcome to Russia (5 points): Make the initial rendezvous with 006 in 'Dam'.
Cheated (3 points): Public Match: Get killed the most times by Oddjob's hat (min 3 deaths).