Firaxis flipped the premise of the 2012 reboot. The aliens won, ADVENT runs Earth's cities as a friendly-looking police state, and XCOM is a guerrilla cell flying a captured alien supply barge called the Avenger. Most tactical missions open in concealment and run on a turn clock, so ambushes beat slow Overwatch creeping. Everything below covers the base game released in February 2016, with the August 2017 War of the Chosen expansion flagged wherever it changes the answer.
This walkthrough takes you from your first session to endgame content. Each phase has specific goals, priorities, and milestones. New to the game? Start with our beginner's guide first.
Quick Progression Summary
| Phase | Area | Focus | Build | Duration |
|---|---|---|---|---|
| 1. Start | Guerrilla Ops | Concealment openers basics | Grenadier | 1-2 hours |
| 2. Early | Retaliation missions | Mission turn timers mastery | Grenadier | 3-5 hours |
| 3. Mid | Supply Raids | Avatar Project doom bar + gear | Ranger or Grenadier | 5-10 hours |
| 4. Late | Alien Facility raids | Build optimization | Ranger | 5-10 hours |
| 5. Endgame | Avenger Defense | Min-max | Ranger or Psi Operative | Ongoing |
See our maps guide for detailed area breakdowns.
Phase 1: Getting Started (Guerrilla Ops)
Three missions appear at once and you pick one. The two you skip each trigger a Dark Event. Objectives are usually a hack, a VIP grab or a device to destroy, and almost all of them carry a turn limit.
Level/Difficulty: Squad of 4 to 6, from month 1 onward Key Rewards: Intel, Supplies, blocked Dark Events, sometimes an Engineer or Scientist
What to Do in Guerrilla Ops
- Learn Concealment openers. Nearly every mission starts with your squad hidden, which lets you walk all six soldiers into flanking positions and set Overwatch before a single shot goes off. Spend your first session getting comfortable with this.
- Pick Grenadier as your starting build. See our builds guide for why.
- Excavate toward a power coil early. A Power Relay sitting on an exposed coil generates double the power of one on plain rock, and a power shortage in month 3 stalls every other Avenger project you had planned.
- Acquire your first equipment upgrade: Shotgun or whatever's available.
- Clear all main content before moving on.
Phase 1 Checklist
- Understand Concealment openers fundamentals
- Grenadier selected and functional
- Guerrilla Ops main content cleared
- Ready for Retaliation missions
Phase 2: Early Game (Retaliation missions)
ADVENT hits a Resistance haven and Faceless hide among the crowd until they transform. The mission ends the instant every alien is dead, and everyone still standing at that moment is saved, so speed protects civilians better than caution does.
Level/Difficulty: Squad of 5 to 6, month 2 onward Key Rewards: Region kept in contact, new recruits, occasionally a Resistance soldier
What to Do in Retaliation missions
- Work on Mission turn timers. Guerrilla Ops and Council jobs usually allow 8 to 12 turns to hack a workstation, plant the X4 charge, or reach the evac zone. This system becomes critical from here on.
- Farm for Shotgun if you haven't already. It's the key upgrade for this phase.
- Guerrilla Tactics School before the Advanced Warfare Center. Squad Size I is the single largest tactical upgrade in the campaign, because a fifth soldier is one more action every turn for the rest of the run.
- Complete all objectives before pushing to Supply Raids.
- Consider whether Ranger might suit your playstyle better than Grenadier.
Phase 2 Checklist
- Mission turn timers integrated into gameplay
- Shotgun acquired
- Retaliation missions fully cleared
- Ready for Supply Raids
Phase 3: Mid Game (Supply Raids)
Convoy and train missions where you loot crates while ADVENT keeps dropping reinforcements. These are among the few untimed maps in the game, but the reinforcement flares never stop, so untimed does not mean relaxed.
Level/Difficulty: Squad of 6, month 2 onward Key Rewards: Large Supplies payout, Alien Alloys, Elerium Crystals
What to Do in Supply Raids
- Master Avatar Project doom bar. Every alien facility ADVENT finishes adds a block to the Avatar bar on the geoscape, and a full bar starts a countdown to campaign loss. This unlocks a new layer of gameplay.
- Start working toward Assault Rifle. It's the best equipment and becomes accessible around now.
- Contact regions in the direction your Resistance Comms capacity can support, not in the direction of the story. Each contacted region adds monthly Supplies, and Supplies gate armor and weapon tiers.
- This area is the main skill check. If you can clear it, you're ready for late game.
- Start investing in Class promotion trees for the tactical depth you'll need going forward.
Phase 3 Checklist
- Avatar Project doom bar mastered
- Assault Rifle acquired or in progress
- Supply Raids fully cleared
- Ready for Alien Facility raids
Phase 4: Late Game (Alien Facility raids)
The only way to pull filled blocks off the Avatar bar. You destroy the facility power source and extract. Garrisons here are heavy enough to punish an undergeared squad badly, so bring your best six.
Level/Difficulty: Colonel-heavy squad of 6, month 3 onward Key Rewards: Avatar Project progress removed, Elerium Cores, alien corpses
What to Do in Alien Facility raids
- Finalize your build. You should be running Ranger or Grenadier with optimized gear.
- Assault Rifle should be your primary. If you don't have it yet, prioritize getting it.
- Research autopsies before you sell corpses. Tygan's autopsy projects gate several Proving Ground items, and the Black Market pays more for corpses later in a campaign anyway.
- Avenger facility rooms optimization starts here. Small improvements compound into massive advantages.
- Farm this area for the resources needed to push into Avenger Defense.
Phase 4 Checklist
- Build fully optimized
- Assault Rifle upgraded to max
- Alien Facility raids fully cleared
- Ready for Avenger Defense
Phase 5: Endgame (Avenger Defense)
ADVENT finds your ship and you fight on your own hull with whoever is healthy. The objective is destroying the alien power source that keeps feeding reinforcements onto the deck. Lose here and the campaign ends outright.
Level/Difficulty: Every available soldier, triggered by story progress Key Rewards: Survival, salvage from the wrecked UFO
What to Do in Avenger Defense
- Avenger Defense tests everything. Come prepared with your best build and gear.
- Magnetic weapons before Predator Armor. Killing an enemy one turn earlier prevents more damage than a single point of armor absorbs, and Modular Weapons plus attachments compound that effect.
- The endgame loop: run Avenger Defense, optimize gear, push harder content.
- Experiment with Psi Operative for a fresh take once you've mastered the standard builds.
- This is where Avenger facility rooms mastery separates good players from great ones. See our tips guide for advanced strategies.
Phase 5 Checklist
- Endgame content on farm
- Best-in-slot gear acquired
- Avenger Defense fully cleared
- Ready for challenge content
Common Progression Mistakes
- Playing Overwatch chess against an 8 turn timer. The mission fails, your soldiers still took the damage, and you get nothing for it.
- Never opening the Black Market. Surplus corpses and captured ADVENT gear are a major Supplies source, and the stock rotates monthly, so a campaign that ignores it stays permanently poor.
- Treating a Sharpshooter like a normal soldier. Squadsight only fires when someone else has eyes on the target, so a Sharpshooter who moves with the pack every turn is throwing away the whole class.
- Letting wounded Colonels heal at base speed. The Advanced Warfare Center cuts recovery time and randomly grants bonus abilities, and a healthy campaign needs about twelve usable soldiers by month 4, not six Colonels and a pile of Rookies.
- Standing next to cars. One stray shot sets a vehicle burning, it explodes a turn later across a wide radius, and the warning is right there on screen the whole time.
Key Tips for Smooth Progression
- Excavate toward a power coil early. A Power Relay sitting on an exposed coil generates double the power of one on plain rock, and a power shortage in month 3 stalls every other Avenger project you had planned.
- Guerrilla Tactics School before the Advanced Warfare Center. Squad Size I is the single largest tactical upgrade in the campaign, because a fifth soldier is one more action every turn for the rest of the run.
- Contact regions in the direction your Resistance Comms capacity can support, not in the direction of the story. Each contacted region adds monthly Supplies, and Supplies gate armor and weapon tiers.
- Research autopsies before you sell corpses. Tygan's autopsy projects gate several Proving Ground items, and the Black Market pays more for corpses later in a campaign anyway.
- Magnetic weapons before Predator Armor. Killing an enemy one turn earlier prevents more damage than a single point of armor absorbs, and Modular Weapons plus attachments compound that effect.
For more advanced strategies, see our tips & tricks guide.
More XCOM 2 Guides
- XCOM 2 XCOM 2 Overview
- XCOM 2 Best Builds
- XCOM 2 Tier List
- XCOM 2 Beginner's Guide
- XCOM 2 Tips & Tricks
- XCOM 2 Weapons Guide
- XCOM 2 Combat Guide
- XCOM 2 Boss Guide
- XCOM 2 Maps & Locations
- XCOM 2 Crafting Guide
- XCOM 2 Classes & Characters
Similar Games
If you enjoy XCOM 2, check out these related guides:
- Sid Meier's Civilization V Walkthrough: strategy game with similar mechanics
- Mount & Blade II: Bannerlord Walkthrough: strategy game with similar mechanics
- RimWorld Walkthrough: strategy game with similar mechanics
