Storyline (EU2012)
XCOM's Objectives
In order to progress in the storyline there are certain milestones that need to be reached. The table below lists the path to completing (and winning the game). Each objective consists of a number of subobjectives that need to be completed before moving to the next.
| Objective | Subobjective | Description |
|---|---|---|
| Capture A Live Alien | Capture a Live Alien Construct the Alien Containment Facility Research the Arc Thrower Build an Arc Thrower Capture a Live Alien Interrogate the Captive Alien | |
| Capture an Outsider Alien | Capture an Outsider Alien Capture an Outsider Alien Research the Outsider Shard | |
| Assault the Alien Base | Assault the Alien Base | |
| Trace the Hyperwave Signal | Research the Hyperwave Beacon Construct the Hyperwave Relay Scan with the Hyperwave Relay | |
| Intercept the Overseer UFO | Research an Advanced Fighter Craft Build the Firestorm Intercept the Overseer UFO Assault the Crashed Overseer UFO | |
| Use the Ethereal Device | Research the Ethereal Device Construct the Gollop Chamber Study a Psionic Alien Build the Psi Labs Facility Test Soldiers for Psionic Powers Increase our Soldiers' Psionic Strength Use the Ethereal Device | |
| Assault the Temple Ship | Assault the Temple Ship |
Storyline Missions
Alien Base
The Alien Base assault is unlocked once you've captured an Outsider and researched it. You will also need to build the Skeleton Key artifact before assaulting it. The Alien Base can be expected to contain all of the aliens you've encountered so far, and at the end a single Sectoid Commander guarding a Hyperwave Beacon. The Alien Base is considerably longer than most missions you'll have done so far, so pack for the long haul. Chryssalids and Drones will show up regardless of current progress.
Overseer UFO
Once you've built a Hyperwave Relay base facility you will gain the ability to detect the Overseer UFO. This can only be shot down with a Interceptor/Firestorm with a powerful weapon. The Overseer UFO is then a standard medium-sized UFO crash site, with the exception that its commander is an Ethereal with Muton Elite guards protecting a Psi-Link device. Sectopod(s) will show up regardless of current progress. If you can't shoot down the Overseer UFO or choose not to assault it after it crashes it will reappear later on.
Temple Ship
The final mission of the game. Your mission is to get to the bridge of the Temple Ship, kill the Uber Ethereal there and keep the Volunteer alive. Your Volunteer soldier is granted a new psionic ability (The Rift) and must survive - if he/she dies you'll lose the game. (But you can restart mission even on Ironman) You can expect to see at least one of every type of alien in this mission. Highlights are a room with two Sectopods, and the final room featuring an Uber Ethereal with two Ethereal guards and several Muton Elites. Killing the Uber Ethereal wins the game immediately, with no need to kill any remaining aliens.