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

Basic Training (20 points): Complete the Answers level of the Campaign.
Dig Two Graves (20 points): Complete the Beasts level of the Campaign.
Mission Accomplished 2.0 (35 points): Complete the Campaign on any difficulty.
Battle-Hardened (50 points): Complete the Campaign on Hard difficulty.
Use More Gun (30 points): Defeat the Vehicle Engineer in the Prejudice level of the Campaign before he deploys a Mech.
A Thorne in their Side (20 points): Complete the Stormfront level of the Campaign.
Star Power (20 points): Earn 20 Stars.
Offline Celebrity (25 points): Earn 40 Stars.
Disconnected Superstar (30 points): Earn 60 Stars.
Citronella Armor (20 points): Win a complete game of Swarm without dying on Medium or harder difficulty.
Against All Odds (10 points): Win a complete game of Swarm.
In the Membrane (30 points): Win a complete game of Swarm on Insane difficulty.
Exterminator (40 points): Win a game on each map in Swarm on Hard or Insane difficulty.
Swarmaholic (20 points): Win a ranked match on each map in Swarm.
Cheetah (10 points): Finish the obstacle course in the Answers level of the Campaign in under 53 seconds.
Conquistador (10 points): Win a complete game in Conquest.
Loud Cartographer (20 points): Win a ranked match in each map group in Conquest.
Face Melter (10 points): Kill an enemy with the Siphon Tool.
Falling with Style (20 points): Kill an enemy by dropping on them.
Napalm in the Morning (25 points): Kill 2 enemies at the same time with Incendiary damage.
'Til It Goes Click (20 points): Kill 3 enemies in a row with the Machine Gun without reloading.
Spice of Life (15 points): Kill an enemy with each weapon type.
The Old One-Two Punch (10 points): Kill an enemy with any weapon after hitting them with a Grenade.
Can I Take Your Pulse? (15 points): Kill 20 enemies with the Pulse Cannon.
Close-Quarters Specialist (15 points): Get 20 Defenses or Denials with the Shotgun.
That's Assault, Brotha (20 points): Kill 5 enemies in a game with the Assault Rifle from over 100m away.
Demolition Man (15 points): Destroy 32 Structures with the Missile Launcher.
Mortardom (15 points): Destroy 5 Vehicles with Mortars.
Knife to Meet You (10 points): Fatality an enemy with the Knife.
Natural 20! (15 points): Kill 20 enemies with headshots using the Sniper Rifle.
It's a Trap! (10 points): Destroy an enemy Detpack.
Garbage Day! (20 points): Complete a ranked match with the highest Combat score using only the Pistol (12 or more players).
Moving Violation (10 points): Kill an enemy by colliding with them using the Bike.
Millennium Club (35 points): Kill 1000 enemies.
Duck Hunt (15 points): Kill 10 enemies with the Deployable AA Turret.
Backseat Driver (10 points): Kill an enemy with any secondary Vehicle seat.
I'm the Juggernaut... (10 points): Kill an enemy by colliding with them while Overdriving.
Like a Boss (50 points): Reach level 50 in ranked matches.
Movin' On Up (10 points): Reach level 2 in ranked matches.
Warmed Up (15 points): Win a ranked match.
32 Pieces of Flair (40 points): Earn each Badge in ranked matches.
Feat-tastic (25 points): Earn each Feat in ranked matches.
Were They Even Trying? (25 points): Win a ranked match while holding the enemy team to less than half your team's VP.
Gotta Cap 'Em All (25 points): Capture each Control Point at least once in a game on a large map.
Fashionista (10 points): Customize your armor type.
Get to da Choppa (15 points): Survive against the Elimination DCM.
Oh, the Irony (10 points): Repair a Supply Depot to full health.
Mission Possible (35 points): Participate in each DCM successfully in ranked matches.
Money in the Banana Stand (15 points): Purchase every Vehicle and Deployable.

Additionally, there is one secret achievement:

My Little Friend (0 points): Kill an enemy with a Micro Beacon.

The following achievements require the "Overdrive Map Pack" bonus downloadable content:

Extra Leg Room (20 points): Win a ranked match on Sky Dock.
I Feel Like Lightning (30 points): Hack a Control Point within 30 seconds in Assault.
Lord of Avernus (20 points): Win a ranked match on Abaddon.
A Pinch of Assault (25 points): Win a complete game in Assault.
Full Assault (25 points): Win a ranked match in each map group in Assault.
1337 sysadmin (35 points): Defuse 20 hacked Control Points in Assault.
Ball Hog (35 points): Capture 20 Control Points in Assault.
Synchronize Our Watches (30 points): Capture 2 Control Points within 10 seconds in Assault.
I Am Legend (30 points): Kill 5 enemies while defending during Sudden Death in Assault.

The following achievements require the "Frontier Colonies Map Pack" bonus downloadable content:

Shutout (20 points): Complete a turn without losing a Control Point in Assault.
Desolator (15 points): Win a ranked match on Desolation.
Watchful Eye (15 points): Win a ranked match on Overseer.