Mass Effect/Walkthrough

Character Creation
When you begin a new game, you have the option of using the default Commander Shepard or creating your own. Creating a custom character allows you to change the Commander's gender, back story, class, and facial features. The first step in creating a custom characters is picking your gender. The choice of gender affects a few small aspects of the storyline including Commander Shepard's choices for the romance subplot. The default names are John and Jane for male and female genders respectively.

The next step is to pick your back story. The following two choices will affect your characters alignment (paragon vs. renegade) and what sidequests you have access to. The default back story for Commander Shepard is Earthborn/Sole Survivor.

Pre-Service History
You have three choices for pre-service history.

Spacer: "Both of your parents were in the Alliance military.  Your childhood was spent on ships and stations as they transferred from posting to posting, never staying in one location for more than a few years.  Following in your parents' footsteps, you enlisted at the age of eighteen."
 * Alignment bonus: ++Paragon
 * Choosing the spacer background grants you access to the "Citadel: Old, Happy, Far-Off Things" mission.

Colonist: "You were born and raised on Mindoir, a small border colony in the Attican Traverse. When you were sixteen, slavers raided Mindoir, slaughtering your family and friends. You were saved by a passing Alliance patrol, and you enlisted with the military a few years later."
 * Alignment bonus: +Paragon, +Renegade
 * Choosing the colonist background grants you access to the "Citadel: I Remember Me" mission.

Earthborn: "As an Earthborn, you had a rough childhood in the slums of Earth, and have a gritty edge to your personality."
 * Alignment bonus: ++Renegade
 * Choosing the Earthborn background grants you access to the "Citadel: Old Friends" mission.

Psychological Profile
You have three choices for you psychological profile.

Sole Survivor: "During your service, a mission you were on went horribly wrong. Trapped in an extreme survival situation, you had to overcome physical torments and psychological stresses that would have broken most people. You survived while all those around you fell, and now you alone are left to tell the tale."
 * Alignment bonus: +Paragon, +Renegade
 * Choosing the Earthborn background grants you access to the "UNC: Dead Scientists" mission.

War Hero: "Early in your military career you found yourself facing an overwhelming enemy force. You risked your own life to save your fellow soldiers and defeat the enemy despite the impossible odds.  Your bravery and heroism have earned you medals and recognition from the Alliance fleet."
 * Alignment bonus: ++Paragon
 * Choosing the Earthborn background grants you access to the "UNC: Espionage Probe" mission.

Ruthless: "Throughout your military career, your have held fast to one basic rule: get the job done. You've been called cold, calculating, and brutal. Your reputation for ruthless efficiency makes your fellow soldiers wary of you. But when failure is not an option, the military always goes to you first."
 * Alignment bonus: ++Renegade
 * Choosing the Earthborn background grants you access to the "UNC: Major Kyle" mission.

Classes
There are three primary and three hybrid classes in Mass Effect.

Soldier
"The Soldier is a tough warrior, able to deal with a range of combat situations. The Soldier gets improved health, has the widest selection of weapons, and is eventually able to wear heavy armor.  Gameplay focus is on getting into the thick of the fight, picking the right weapon for tactical situations, and outlasting opponents."

Soldiers are adept at physical combat and can take quite a beating. Soldiers can specialize in all four weapon types and can wear heavy armor. On the other hand, soldiers cannot biotic or tech abilities. Soldiers will have a hard time finding items without a character with tech abilities in his party. Choose this class if you plan on brute forcing your way through the game. Soldiers will later be able to take the Commando or Shock Trooper specialization.

Engineer
"The Engineer is a tech specialist, able to quickly and easily manipulate the environment with specific talents. Gameplay focus is on shaping the battlefield during combat, healing the party, and debuffing enemies (disabling weapons and lowering shields)."

Engineers are very good with technology, allowing them a wide range of tech skills that can disable mechanical enemies. They can decrypt locks, giving access to a wide array of items throughout the game. Engineers may only use a pistol to begin with, but will eventually unlock the ability to wear light armor. Engineers focus on debuffing enemies and healing allies. They may venture into the Medic or Operative specializations.

Adept
"The Adept is the ultimate biotic, able to affect the physical world with the power of the mind. They can use biotics to violently manipulate objects in the environment, including nearby enemy targets.  Gameplay focus is on disabling and debuffing enemies while dealing massive amounts of damage."

Adepts are master of biotic combat, allowing them to disable enemies and damage them with magic-like abilities. Adepts can throw enemies through the air, or hold them in place so they cannot defend or attack. On the other hand, adepts do not have much defense and can only use light armor. Also, they are only trained in pistols. Adepts can later take the Bastion or Nemesis specialization.

Infiltrator
"The Infiltrator is a tech-savvy warrior, able to win battles by quickly disabling and killing enemies. These soldiers focus on unlocking alternate routes, gaining access to good equipment, and obtaining an advantageous position over enemies in combat."

Infiltrators are a combat/tech hybrid with a focus on first disabling and then killing enemies. Infiltrators may use both pistols or sniper rifles and can wear medium armor. Infiltrators may choose either the Commando or Operative specializations.

Vanguard
"The Vanguard is a powerful combatant, able to combine the offensive powers of the Adept and the Soldier. They have access to various weapons and armor, as well as biotics. Gameplay focus is on taking down enemies with quick and brutal force.

Vanguards are the combat/biotic hybrid of the game, with a focus on offensive powers. Vanguards may use either pistols or shotguns and can wear up to medium armor. Vanguards may specialize as either a Shock Trooper or Nemesis.

Sentinel
"The Sentinel is the most flexible class, able to combine tech and biotics to manipulate the environment, disable and track enemies, or defend the party. Gameplay focus is on protecting the party using kinetic barriers and healing it with advanced medical training."

Sentinels are a biotic/tech hybrid that specialize on disabling enemies and defending the team. The sentinel may use pistols and may wear light armor, making them fairly ineffective in close combat. However, there ability to disable enemies is unmatched. Sentinels may choose to specialize as either a Bastion or Medic.

Facial Appearance
The final step is to customize your characters appearance. You may change the size, shape and color of Commander Shepard's hair, forehead, brow, eyes, nose, cheeks, jaw, chin, and lips. You may also add a scar or facial hair.

Once you are ready, choose "Finalize" to begin the game.