Just over two years after BioWare’s original space-RPG epic hit the Xbox 360, its much-anticipated sequel has finally arrived. A much darker, more serious affair than the first title, Mass Effect 2 is a western-RPG with so many paths through the game, you’ll need a walkthrough just to comprehend it all. And that’s where we come in. Our gigantic walkthrough is rounded out by a robust basics section, coverage on all side quests, and even the game’s entire codex, for all of you nerds out there.

It’s time to save the galaxy!… again.

Mass Effect 2 Achievement Guide

Missing in Action (5)
Save your crew from an overwhelming attack

Very Elusive (10)
Return to active duty

The Convict (10)
Successfully recruit the biotic Convict

The Krogan (10)
Successfully recruit the krogan

The Archangel (10)
Successfully recruit Archangel

The Professor (10)
Successfully recruit the Professor

The Quarian (10)
Successfully recruit the quarian

The Justicar (10)
Successfully recruit the Justicar

The Assassin (10)
Successfully recruit the Assassin

Friend or Foe (10)
Obtain geth technology

Colony Defense (25)
Defend a human colony from attack

The Prodigal (10)
Gain the loyalty of the Cerberus Officer

Ghost of the Father (10)
Gain the loyalty of the Cerberus Operative

Catharsis (10)
Gain the loyalty of the biotic Convict

Battlemaster (10)
Gain the loyalty of the krogan

Fade Away (10)
Gain the loyalty of Archangel

The Cure (10)
Gain the loyalty of the Professor

Treason (10)
Gain the loyalty of the quarian

Doppelganger (10)
Help the Justicar resolve her mission

Cat’s in the Cradle (10)
Gain the loyalty of the Assassin

A House Divided (10)
Hack a geth collective

Ghost Ship (25)
Complete the investigation of a derelict alien vessel

Suicide Mission (50)
Use the Omega 4 Relay

Mission Accomplished (125)
Save humanity throughout the galaxy from certain annihilation

Against All Odds (15)
Survive suicide mission

Insanity (75)
Complete the game on the “Insanity” difficulty level without changing the setting

No One Left Behind (75)
Keep your team alive through the suicide mission

Long Service Medal (75)
Complete Mass Effect 2 twice, or complete it once with a character imported from Mass Effect 1

Paramour (50)
Successfully pursue a relationship with a teammate

Head Hunter (10)
Perform 30 headshot kills with any weapon on humanoid targets

Brawler (10)
Shoot and kill 20 enemies while they’re knocked back by a punch

Big Game Hunter (10)
Thresher Maw defeated

Tactician (10)
Hit 20 different targets with multiple biotic powers to combine the effects

Master at Arms (15)
Kill enemies with 5 different heavy weapons during the game

Merciless (10)
Make 20 enemies scream as they fall or are set on fire

Overload Specialist (15)
Disrupt the shields of 25 enemies

Warp Specialist (15)
Warp the barriers of 25 enemies

Incineration Specialist (15)
Incinerate the armor of 25 enemies

Operative (15)
Complete a mission discovered by scanning an unexplored world

Agent (50)
Complete 5 missions discovered by scanning unexplored worlds

Prospector (5)
Retrieve mineral resources by scanning and probing a planet in the galaxy map

Explorer (10)
Visit 100 percent of the planets in an unexplored cluster

Power Gamer (10)
Reach Level 30 with one character

Scholar (15)
Unlock 15 new Mass Effect 2 codex entries

Technician (15)
Obtain (10) technology upgrades

Weapon Specialist (15)
Fully upgrade a weapon

Scientist (10)
Complete any research project in the Normandy’s laboratory

Fashionista (5)
Personalize your armor in your quarters on the Normandy

Power Full (15)
Evolve any power

Highly Trained (15)
View all advanced combat training videos at Shepard’s private terminal.