Welcome to XCOM: Enemy Unknown, Commander. You're in charge of a global paramilitary organization tasked with defending Earth from an escalating alien invasion. Every turn, you'll be making critical decisions: managing your base, researching alien technology, and, of course, leading your hand-picked squad of soldiers on high-stakes tactical missions across the globe. It's a tense, atmospheric strategy game where every decision matters, from the gear you equip to the research you prioritize.
This guide is here to help you navigate the complexities of XCOM. We'll cover everything from the fundamental combat mechanics and resource management to more advanced strategies for tackling challenging missions like alien base assaults and the final confrontation on the Temple Ship. Whether you're aiming to unlock all the Steam Achievements or just want to ensure Earth's survival, we've got you covered.
Part 1
Your first steps into XCOM: Enemy Unknown! Learn about setting up your game, understanding Second Wave mods, and choosing your starting country to begin your fight against the aliens.
Alright, let's get you started with XCOM: Enemy Unknown. This first part is all about getting your game set up just right before you even drop your first soldier into the field. Think of it as prepping your gear before a big mission – crucial stuff!
First things first, when you fire up a new game, you'll see a bunch of options. You can randomize soldier stats, pick which DLCs you want active, decide if you want the game to be a bit more forgiving with saving (called 'save scumming'), and even turn off that sometimes-annoying tutorial. If you're new to this, I highly recommend enabling 'Second Wave' and the 'Save Scum' option. Turning off the tutorial is also a good shout so you can learn at your own pace. For this guide, we'll assume you're playing on Classic difficulty, with all DLCs enabled, and no extra difficulty-spiking Second Wave mods.
Now, about those 'Second Wave' mods. Some of them just tweak how the game plays, but others can really crank up the difficulty. The 'Save Scum' mod is a lifesaver, especially with XCOM's sometimes wild random number generator. Basically, XCOM decides if a shot hits or misses *before* it even happens. Without Save Scum, if your 90% shot misses, it's just missed. With it enabled, reloading your save lets the game re-roll those dice, giving you another chance to avoid those frustrating moments where all your soldiers seem to miss every single shot. It's a reference to the gaming term 'save scumming,' where you reload to get a better outcome. If you're okay with accepting the occasional bizarre failure, you might not need it, but for a smoother ride, I'd keep it on.
There's also a mod called 'Aiming Angles.' This one gives bonuses to aim if your soldier is flanking an enemy. In the original XCOM, sometimes bullets would just magically hit cover instead of the target, which was a big complaint. This mod helps make combat feel a bit more logical by rewarding good positioning.
Part 2
Explore XCOM: Enemy Unknown mods like Training Roulette, Itchy Trigger Tentacle, and Red Fog. Learn their effects and availability.
Mods from the original XCOM: Enemy Unknown:
Flanked Mod (a community-made modification that changes the game): This mod makes combat more tactical by emphasizing flanking, but also makes aliens more dangerous if your soldiers are exposed. It considers only whether an enemy is flanked or not, removing nuanced positioning benefits.
Training Roulette: This mod randomizes the skill tree for every soldier class except MEC Troopers. This blurs class distinctions but can lead to soldiers with unsuitable skills (e.g., a Heavy with close combat skills). It is not recommended due to increased randomness and potential for making classes less effective. Soldiers at the Squaddie rank (the first rank above Rookie) display all possible skills, allowing for early dismissal of those with undesirable trees.
Itchy Trigger Tentacle: Not available until you've beaten the game. This mod causes Mechtoids, Cyberdisks, and Sectopods to fire half the time instead of activating overwatch. The spotting soldier can finish their move, potentially reaching cover (press the cover button to crouch behind walls or objects). This mod increases game difficulty.
Mind over Matter: Not available until you've beaten the game. Giving a soldier a Gene-mod disqualifies them from psionic potential, preventing the creation of psionic genetic supersoldiers. This means you must settle for regular psionic soldiers. The source suggests psionics are generally useless, so this mod is not seen as a significant difficulty increase.
Mods from the original X-com Enemy Unknown (re-listed):
Damage Roulette: Guns deal random damage, making combat more unpredictable, similar to UFO Defense where pistols could deal double damage.
New Economy: Council nations provide random amounts of funds, which is described as not very interesting or deadly.
Not Created Equally: XCOM rookies start with random stats, potentially leading to soldiers who panic easily and have poor aim. This mod also randomizes movement speed, affecting soldier effectiveness significantly. Soldiers can have high movement and stats or average movement with weak aim and low will.
Hidden Potential: XCOM soldiers gain random stats upon ranking up, meaning a sniper might receive less aim bonus than a Heavy. This is useful for those who enjoy randomness.
Red Fog: Only available after beating the game on Normal difficulty. Combat wounds reduce soldier abilities, preventing near-dead soldiers from performing effectively. This mod forces players to protect soldiers and reduces the capability of units like SHIVs and MECs.
Absolutely Critical: Only available after beating the game on Normal difficulty. Any unit that is flanked receives a critical hit if the flanker hits. This makes ambushes deadly and emphasizes the importance of the cover system.
Greater Good: Only available after beating the game on Normal difficulty. Psionics can only be learned by capturing a psionic alien. Killing psionic aliens prevents psionic acquisition if this mod is active. This is not considered a major game changer as capturing aliens is generally recommended, and players should have sufficient firepower and tactical sense by the time they encounter psionic aliens.
Marathon: Only available after beating the game on Normal difficulty. All game activities take longer to complete.
Results Driven: Only available after beating the game on Classic difficulty. Nations provide less money as they become more insecure, increasing difficulty on harder settings due to panic from alien abduction missions.
High Stakes: Only available after beating the game on Classic difficulty. Players receive random rewards for completing Alien abduction missions, preventing the farming of engineers.
Diminishing Returns: Only available after beating the game on Classic difficulty. Satellites cost more to construct as more are built, potentially leading to the loss of a few continents.
More Than Human: Only available after beating the game on Classic difficulty. Psionic soldiers are harder to find, extending the late game.
War Weariness: Only available after beating the game on Impossible difficulty. Nation funding decreases as the game progresses, encouraging faster completion.
E-115: Only available after beating the game on Impossible difficulty. Elerium supplies degrade over time, providing more incentive to shoot down alien ships.
Total Loss: (No details provided in source.)
Part 3
Unlock XCOM: Enemy Unknown's secrets in Part 3. Learn about the tutorial, country selection bonuses, and long-term strategic planning for base management and alien conquest.
- 1The Tutorial (TUTO): It is strongly recommended to turn off the in-game tutorials. While they guarantee a Heavy class soldier, they also lead to soldier deaths and wasted resources. The Meld Tutorial's effect is random, with Dr. Valhen explaining Meld when encountered. Turning off the tutorial provides a starter mission fighting Sectoids based on difficulty (Impossible has 8, Classic has 6, Normal/Easy have 4). After the opening cutscene, follow Bradford's instructions in Germany. Expect to lose 3 soldiers before the main game begins, but you will receive a Heavy.
- 2Base Structure and Long-Term Goals: This section focuses on base management and long-term planning. The key to an easier experience is to take your time. Rushing will empower the enemy while your soldiers lack necessary weapons, armor, and experience. For example, refusing to capture the crystal energy alien will cause the advisor to admonish you, and the game will ramp up difficulty. Prolonged refusal may lead to this alien appearing in groups of up to three, but by then, you should be equipped to handle them. The proposed strategy prioritizes early-game risk for minimal nation withdrawal due to high panic.
- Second Wave Modifiers: These can be altered in the pause menu but may disqualify you from achievements.
- Power Generating Facilities: These cost more to build, and nuclear power is not an option.
- Soldier Equipment: If a soldier dies, their equipment is destroyed. Aliens design their weapons to self-destruct.
Country Selection (PICK): Choose your base location carefully, as the starting continent provides a permanent bonus, achievable only with full satellite coverage and no withdrawn nations. These bonuses are difficult to earn, with most players obtaining only 2-3. Recommendations are South America or Africa.
- North America - 'Air and Space': Aircraft and their weapons cost 50% less to build and maintain. Diagnosis: Fairly useless unless acquiring late-game; early-game savings on single interceptors are minor.
- South America - 'We have ways': Interrogations and autopsies complete instantly. Diagnosis: Extremely useful. Faster analysis leads to research credits, speeding up research. Also enables gene mods and enhances MEC Trooper damage.
- Asia - 'Future Combat': Foundry projects and Officer Training School programs cost less. Diagnosis: Mostly useless as a first bonus. Foundry projects require research and pay off late-game. OTS programs are not overly expensive, and essential skills can be acquired later.
- Europe - 'Expert knowledge': Laboratories and workshops cost 50% less to maintain and build. Diagnosis: Useless unless planning an elaborate base with many labs/workshops. You'll likely build only one or two workshops. Labs are generally useless, though they can prevent EXALT research raids.
- Africa - 'All in': All nations provide 30% more money. Diagnosis: Absolutely useful. This bonus fuels satellite construction, base expansion, better nation coverage, more bonuses, and ultimately, superior weapons and research, leading to victory.
Managing the World and Long-Term Strategy (STYU): This section is for players new to XCOM: Enemy Unknown who need guidance on game mechanics and long-term planning. The strategy proposed involves taking risks early to minimize panic and nation withdrawal.
Part 4
Learn XCOM: Enemy Unknown base building, facility bonuses, and research priorities. Sell UFO power sources for cash.
- 1From the base menu, click 'Engineering' and then 'Build Facilities' to construct structures and excavate ground.
- 2Designate one side of your base for Satellite Uplinks, building them adjacent to existing ones for bonuses.
- 3Immediately build an Access Lift and begin excavating.
- 4Cue up 2-3 extra satellites as Satellite Uplinks are limited by power and available engineers.
- 5Build Power Generators on the side of the base not used for Satellite Uplinks.
- 6On this side, also build the Officer Training School, Cybernetics Lab, or Gene Mod (a community-made modification that changes the game) Labs, depending on your chosen strategy.
- 7To start research, click 'Research' and select 'Start New Research Project'.
- 8Prioritize researching 'Alien Materials' for increased soldier HP or 'Weapon Fragments' for better weapons; the latter is recommended for combat effectiveness.
- 9Researching weapon fragments unlocks 'Experimental Warfare' and potentially plasma weapons if you capture specific UFO components.
- 10Avoid researching 'Xenobiology' early on, as capturing live aliens is not very rewarding until later in the game, unless you have the South America continent bonus.
- 11Wait until Mutons become common before capturing aliens; capturing Muton Elites can provide advanced plasma weapons.
- 12After building facilities, recruiting soldiers (rarely), and setting research, click the globe and then the 'Scan' button to advance time and trigger events like abduction missions, council missions, or UFO sightings.
- Buildings gain bonuses when similar types are grouped together horizontally or diagonally.
- Satellite Uplinks are limited by power and the number of available engineers.
- Do not demolish existing buildings or build Laboratories early on.
- Only upgrade soldiers if absolutely necessary or if you have excess cash.
- Shoot down UFOs, capture their power sources and flight computers intact, and sell them for cash to fund base construction and prevent nations from leaving the XCOM project.
- Researching weapon fragments is generally more beneficial early game due to combat mechanics.
- Capturing late-game aliens provides stronger plasma weapons, reducing research time for the plasma weapon tree.
- If you wait until Muton Elites are common, you can capture one and research its gun for significant plasma tech benefits.
- Interceptor armaments and air combat are detailed in section 3B.
- Tactical mission management is covered in section 3.
- Council missions are random, except for specific DLC (downloadable content — extra missions or items released after launch) missions.
- UFO interception with a standard interceptor (the raven) and basic missiles is capable against most alien craft; one interceptor with a laser cannon can handle most UFOs except battleships.
- Failing to intercept UFOs can lead to battleships attacking satellites.
- On difficulties lower than Impossible, UFO interception is generally easy; maintaining one or two basic interceptors per continent is usually sufficient.
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