Special Feature: The Evolution of XCOM
Introduction
In 2012, Firaxis Games released XCOM: Enemy Unknown (EU), a turn-based strategic combat game inspired by the classic X-COM: UFO Defense from 1994. In the face of invasion from a hostile and technologically superior alien collective, humanity unites behind the XCOM project, a secret international military organization. As the commander of XCOM, the player must direct tactical engagements, aerial interceptions, personnel management, and reverse engineering efforts to combat the alien threat. The game was universally praised as a paragon in the genre, winning Game of the Year and Best Strategy Game awards from dozens of publications.
Roughly a year later, XCOM: Enemy Within (EW) was released as an expansion for EU. It augmented the arsenal on both sides of the war: more alien types, better enemy AI, more diverse missions, but also more tech options for the player and a more balanced perk tree. Seeing the vast potential that the XCOM system had to offer, a team of modders quickly began work on what became known as Long War (LW). Simply put, LW transforms the XCOM experience from a game to a simulation, adding depth, complexity, and realism to every element.
In 2012, Firaxis Games released XCOM: Enemy Unknown (EU), a turn-based strategic combat game inspired by the classic X-COM: UFO Defense from 1994. In the face of invasion from a hostile and technologically superior alien collective, humanity unites behind the XCOM project, a secret international military organization. As the commander of XCOM, the player must direct tactical engagements, aerial interceptions, personnel management, and reverse engineering efforts to combat the alien threat. The game was universally praised as a paragon in the genre, winning Game of the Year and Best Strategy Game awards from dozens of publications.
Roughly a year later, XCOM: Enemy Within (EW) was released as an expansion for EU. It augmented the arsenal on both sides of the war: more alien types, better enemy AI, more diverse missions, but also more tech options for the player and a more balanced perk tree. Seeing the vast potential that the XCOM system had to offer, a team of modders quickly began work on what became known as Long War (LW). Simply put, LW transforms the XCOM experience from a game to a simulation, adding depth, complexity, and realism to every element.
All versions of XCOM feature a gameplay mode known as Ironman, in which the game runs on a continuously updated save file -- all decisions are final, and their consequences are permanent. Much to the surprise of the developers, Ironman was embraced as the definitive XCOM experience. The combination of Ironman with Impossible (the game's highest difficulty setting) is known simply as I/I, the ultimate challenge. Among the tens of thousands of Steam users who have played any version of XCOM, roughly 1% have successfully completed an I/I campaign. |
The evolution of XCOM can provide us with rare insight into the iterative design process. Having three distinct games built using the same engine would be privilege enough as is, but the granularity actually goes even deeper: LW went through 15 beta versions before the final release, with each version being tweaked based on the feedback of the most successful players. In this special feature, I will apply the same gameplay constraints to EU, EW, and LW to evaluate the work of the many designers and testers who have contributed to the XCOM experience. Those constraints:
- Impossible Ironman
- No robotic units
- No genetic modifications
- No invisibility
- No plasma weapons
Part One: Enemy Unknown
The first game in the challenge is EU. While the lower difficulty settings are designed to be fun and reasonably fair, Impossible was designed, appropriately enough, to be impossible. Even in the very first mission, the aliens have more units on the field, each with better aim and a higher chance to score a critical hit. Any time a human soldier is killed or injured, nearby allies are likely to panic and lose their turn (or worse), while the aliens never panic. After each month of in-game time, one or two new alien units are added to the field to increase the difficulty of combat. The player starts drastically far behind the difficulty curve, and the alien tech charges forward whether the player is ready or not.
The strategic layer is not any more forgiving. Most missions offer a choice between operation sites in three different countries. Whichever two countries are not chosen will immediately reach maximum panic level, causing them to cut funding to the XCOM project at the end of the month. The campaign ends if 8 of the 16 council nations leave. In short, the game must be beaten before it beats the player.
The first game in the challenge is EU. While the lower difficulty settings are designed to be fun and reasonably fair, Impossible was designed, appropriately enough, to be impossible. Even in the very first mission, the aliens have more units on the field, each with better aim and a higher chance to score a critical hit. Any time a human soldier is killed or injured, nearby allies are likely to panic and lose their turn (or worse), while the aliens never panic. After each month of in-game time, one or two new alien units are added to the field to increase the difficulty of combat. The player starts drastically far behind the difficulty curve, and the alien tech charges forward whether the player is ready or not.
The strategic layer is not any more forgiving. Most missions offer a choice between operation sites in three different countries. Whichever two countries are not chosen will immediately reach maximum panic level, causing them to cut funding to the XCOM project at the end of the month. The campaign ends if 8 of the 16 council nations leave. In short, the game must be beaten before it beats the player.
The clock is always ticking on Impossible Ironman.
There are a few saving graces that make I/I possible, even with extra constraints added:
- While enemy units have strong stats, their AI is quite poor in certain scenarios. Tactics in the early game rely heavily on identifying key areas of engagement where this advantage can be abused.
- Explosives are severely overpowered due to their guaranteed damage output and the low durability of cover. A single well-placed grenade can expose and weaken an entire enemy squad for easy kills.
- Although the player starts behind the difficulty curve, a well-planned research path can remedy this within a few in-game months. Once ahead, it's relatively easy to stay ahead.
- If the player can attain full satellite coverage, the number of missions per month drops significantly, which helps to reduce the impact of injured soldiers spending time in the medbay.
- The urgency to complete the campaign quickly means the aliens can be denied the opportunity to deploy their most dangerous units.
Constraint |
Evaluation |
Impossible Ironman |
Hardest during the first month of the campaign. The difficulty generally declines as the player gains access to tactical resources, particularly squad size upgrades, higher ranked soldiers, and more powerful weapons. |
No robotic units |
Most detrimental on Bomb Disposal missions, which feature a strict time limit and poison-spewing enemies. Robots have high mobility and immunity to poison, making them a natural choice here. Several campaigns were abandoned due to losses on these missions. |
No genetic modifications |
Does not apply to EU. |
No invisibility |
Largely irrelevant. The game can be beaten before Ghost Armor becomes available. |
No plasma weapons |
Most noticeable on the Overseer mission, which features multiple squads of Muton Elites and Sectopods, powerful enemy units with massive health reserves. While the available firepower is noticeably diminished by ignoring plasma weapons, the challenge is mitigated by the fact that the campaign is almost over at this point. Losses are unlikely to have any impact on the campaign, so units can be sacrificed to ensure the mission's success. |