Call of Duty: Modern Warfare (2019) - Theoretical Analysis of Weapon Stats Balance
Note: The original article was completed in mid-2020, and the examples of games mentioned are only applicable to the situation at that time. It is now being reposted on my personal website.
Call of Duty: Modern Warfare 2019 (CODMW) stands out as one of the top multiplayer shooters in terms of gameplay feel, and its excellence in gunplay design plays a significant role in this. This report aims to delve into the theory behind the game's gun stats balance.
The core player experience in the COD series is epitomized in the Team Deathmatch (TDM) mode - the objective being to eliminate all enemies. Whether it's the gameplay mechanics, firearms, or map design, COD's identity as a fast-paced, entertaining shooter dictates that every design element is tailored to enhance the shooting and killing experience. The various in-game designs are interdependent, collectively contributing to the exceptional feel of the COD series. Designing any element in isolation, or transplanting it into another shooter, would result in a loss of the intended essence due to the lack of integrated design. Therefore, this analysis will inevitably touch upon other systems or elements in the game. These designs are interconnected and causally related. Although I would like to analyze all aspects, this report will primarily focus on gun stats and two related aspects, constrained by length and preparation time.
The current generation of Modern Warfare offers a highly versatile Gunsmith system, allowing players to modify a range of gun stats within certain limits. However, the overarching principle of gun stats design in the game remains consistent with previous generations. The core balance theory revolves around appropriate engagement distances and a balance between offensive and defensive playstyles. This principle ensures that each weapon has its ideal scenarios and playstyles. The outcome of an engagement where players use different weapons is influenced not just by their shooting skills but also by which environment favors which weapon more. If a player possesses excellent "awareness" and can maneuver engagements to occur in scenarios that favor their weapon, then even a player with lesser shooting skills can achieve relatively good results. This principle of balance, especially in a fast-paced mode like TDM with evenly distributed engagement locations, is showcased to its fullest extent.
Appropriate Engagement Distance: TTK-Distance Curve
As illustrated in the graph, this represents the change in the number of bullets to kill for assault rifles and submachine guns in MW at varying distances. Generally, assault rifles are seen as the most versatile weapons, effective at all ranges, while submachine guns hold a significant advantage at close range. When an assault rifle user encounters a submachine gun user at medium to long range, the assault rifle is more advantageous, and the opposite is true at close range. This establishes a balance with both gameplay significance and playability.
In MW, this advantage of distance is depicted through the weapon's damage decreasing stepwise with distance. Different weapons have set damage values at various ranges. By converting the number of bullets to kill and the rate of fire, one can calculate the Time-to-Kill (TTK) for respective ranges. TTK is the primary metric in weapon balancing. When other attributes are not considered, the weapon with a shorter TTK at a specific range is more advantageous.
Other games, like Apex Legends, do not use TTK as a metric for determining advantageous distances. Most weapons in these games maintain consistent damage values across all ranges, meaning the theoretical TTK remains unchanged. These games achieve distance balance through other ballistic properties, including bullet velocity (bullet drop), recoil intensity, shooting accuracy, and random spread, etc. MW does not follow this method, mainly due to its "laser gun" shooting feel. In MW, most firearms, when aimed down sights (ADS) within their effective range, exhibit minimal random bullet spread and very low recoil, making them much easier to control compared to other shooting games. The game almost entirely avoids the frustrating shooting experience of "aiming correctly but depending on luck due to random spread" to hit the enemy. As long as the player can aim accurately (hit the first shot) and control the recoil, combined with the generally short TTK that doesn't require much tracking, players can easily eliminate enemies. COD's shooting feel significantly advantages players who spot and aim at the enemy first. Even beginners, if they get the chance to flank or aim at an enemy from the side or back, can take advantage of this to eliminate more experienced players. Situations common in other shooting games, where a beginner gets the first shot but still gets outplayed by an experienced player, are less frequent in COD. In terms of recoil feel design, COD adheres to the principle of "immediately rewarding correct player actions," leading to the necessity of using damage attenuation and TTK differentiation for balancing advantageous distances.
The use of stepwise rather than linear damage attenuation is because COD's TDM mode generally features smaller maps with numerous but limited types of engagement scenarios. Stepwise damage attenuation allows players to intuitively judge whether the current engagement scenario is advantageous for them. By controlling the distance of hotspots on the map and the weapon's advantageous range, players can judge TTK based on specific map locations without needing a strong sensitivity to distance, thus lowering the difficulty in developing game awareness. For example, if one hotspot is at 14 meters and another at 16 meters, and the weapon's TTK phase division is at 15 meters, players should generally expect not much difference in weapon advantage between these two hotspots. Precise distance judgment is challenging for players, and if the aforementioned situation occurs, players might feel that the weapon's performance is unstable. Similar distances in scenarios could result in a clear TTK distinction. In such cases, it's possible to fine-tune the layout of cover in the map to ensure that the distances of hotspots avoid being too close to the weapon damage step boundaries. If the damage attenuation were purely linear, resulting in an almost linear TTK attenuation, it would be challenging to provide more distinction for weapon usage distances. If it were a piecewise linear function, maintaining the numerical model for COD, with an average maximum engagement distance of 50 meters, would be more troublesome. It would also be more challenging to control the relationship between map engagement hotspot distance design and firearm balance, making stepwise attenuation functions more convenient for data maintenance.
Of course, if the design of the map's engagement hotspots is more complex, or if there are many open areas that allow players' movement to easily cause linear changes in engagement distances, and the shooting game has a longer TTK, then for such games, a piecewise linear function for damage curves makes more sense. There are more sensitive points for lethal distances, and players' evasive maneuvers ("snake-like movements") are more likely to help them avoid death. Additionally, for shooting games without a "regenerative health" system, a segmented linear damage curve can provide more direct damage rewards for engagement distances, consuming more of the hit player's health recovery resources, as seen in games like PUBG and the Battlefield series. COD, including its own battle royale mode Warzone, offers a different experience from these elements, leaning more towards fast-paced kills in single engagements and continuous respawning and combat. In this context, the stepwise attenuation model it adopts is indeed the optimal solution for its gaming experience.
Lastly, it's worth noting that the MW series is themed around modern warfare, and when designing weapons, the rate of fire needs to reflect the theoretical rate of fire of real weapons, which is not a parameter with high flexibility. Therefore, controlling TTK relies on the flexibility of damage values. However, the selection of weapons with different rates of fire for inclusion in the game is partly because popular firearms inherently have different rates of fire, and also because it allows players to experience different shooting and recoil control feels under the same TTK standards, through variations in rate of fire.
Offensive and Defensive Gameplay: ADS and Recoil Characteristics
Most popular CODMW maps are relatively compact, leading to generally shorter engagement distances in-game. Under this condition, the game's shooting strategy is mainly divided into two categories: offensive 'Rush' and defensive 'Holding Points'. Rush players rely on quickly moving between covers and, upon close encounters with enemies, can utilize the hip-fire accuracy and short TTK of weapons like submachine guns or shotguns to rapidly eliminate opponents. Defensive players, on the other hand, position themselves behind specific covers and enter ADS in advance, aiming at locations where enemies are likely to appear (usually within the effective range of their weapon). When an enemy appears, they fire immediately, utilizing the precision bonus of ADS to eliminate the enemy.
The above diagram represents the timeline of player actions during an engagement. Note that this diagram only shows the time segments involved; the length of the lines does not represent the duration of time. Different weapons have varying sprint-out times and ADS times. The TTK is the expected time to kill based on the actual engagement scenario and hit rate, which varies with each scenario.
In offensive gameplay, from encountering an enemy to actually killing them, players go through the weapon's sprint-to-fire time + ADS time. Weapons suited for offensive play, like pistols and submachine guns, have shorter times for both, and generally possess good hip-fire performance. Upon close encounters with enemies, they can rely on faster ADS time or higher hip-fire accuracy to kill enemies more quickly. The viability of this playstyle depends on COD's extremely short TTK at close range. On average, in close-range engagements, the sum of the weapon's sprint-to-fire time + ADS time is roughly 1:1 proportional to the TTK time, both being in the order of 200ms. Therefore, offensive weapons that significantly reduce the time before firing can have enough advantage in this context. If the game's pace is generally slower and the TTK time far outweighs the pre-firing action time, even a hip-fire laser gun wouldn't provide enough advantage, making this playstyle unviable. And naturally, these weapons suffer from damage attenuation and bullet spread at long range, resulting in a longer TTK. In such cases, the TTK time significantly outweighs the pre-firing action, putting offensive weapons at a disadvantage in long-range engagements.
In defensive gameplay, players pre-mount or ADS in advance. These types of weapons generally have longer ADS times and are not suited for offensive play, such as light machine guns and sniper rifles (in this generation, rush sniping is almost non-existent). However, once they fire, with the precision bonus from pre-aiming in ADS, they have a higher hit rate and shorter expected TTK than rushing enemies, resulting in a shorter overall kill time. An extreme example is a sniper rifle set up in advance; if an enemy appears in the field of view, the player only needs the reaction time to aim and fire, achieving an immediate hit and kill, making the theoretical TTK 0ms. However, while in ADS, the player's movement speed is nearly halved, making it harder to dodge enemy fire through quick movement, and they may also be vulnerable to enemies outside their field of view. This playstyle relies on the player's familiarity with the map, understanding of the weapon's effective range, and anticipation of enemy positions on the battlefield. Generally, the larger the map, the more advantageous positions it offers for holding points, and the more players are inclined to use this playstyle. However, based on the popularity of various maps and player opinions, purely defensive gameplay is not very popular, and the controversy around 'campers' has always been significant.
Finally, there's the balanced playstyle that occurs during sudden encounters with enemies, such as when two assault rifle players engage each other at medium range. In COD, except for submachine guns, other weapons have a significant hip-fire accuracy penalty, so most players will ADS before firing. At this point, the theoretical advantages and counterplay between the two weapons depend on their respective ADS time plus the TTK time at the engagement distance. The most balanced playstyle, in fact, involves dynamically switching between offensive and defensive playstyles. For example, with an assault rifle, within close-range engagement distances, players can gain a defensive advantage by pre-aiming to prevent being rushed. When moving between covers, they can rush quickly. At medium range, where they encounter enemies, as it's their optimal engagement distance, they can use a balanced approach of normal ADS + advantageous TTK duration to eliminate the enemy. At long-range engagements, they can kill enemies through a defensive playstyle of pre-holding positions. However, this playstyle is the least distinctive in COD and requires a lot of maps with medium-range engagement areas for support. Extremely compact or very open maps, on the other hand, tend to favor offensive or defensive playstyles.
In COD, recoil characteristics are primarily designed to further reinforce the advantages and counterplay of different weapons at various engagement distances. Regarding recoil characteristics, COD has the following parameters:
Recoil Offset Curve: When a weapon is fired continuously, whether in ADS or hip-fire, the crosshair will move along a fixed curve with some random spread noise. Different weapons have different recoil offset curves, and the shape of these curves corresponds to different recoil control experiences. Generally, the lower the basic curve offset and the more even the offset rhythm, the easier it is to control recoil, and the greater the advantage at long range. Some weapons have uneven offset rhythms, like the AK-47, where the initial few bullets have a much higher muzzle jump than subsequent ones, making it difficult to control recoil and track targets at long range.
Hip-Fire Spread Degree: From pistols, submachine guns, assault rifles, to light machine guns, the hip-fire spread increases respectively. The lower the hip-fire spread, the more suitable it is for offensive gameplay involving direct rushing and hip-fire shooting at close range. Some pistols, when equipped with attachments that increase hip-fire accuracy, can almost exclusively be used for hip-firing. Additionally, hip-fire spread decreases when standing, crouching, or prone, but whether this is a separate value setting for each weapon or a uniform ratio has not been tested and no data was found. After all, players in these low-mobility states generally choose ADS for precision.
ADS Spread Degree: In COD's shooting experience, most weapons have relatively low ADS spread compared to other games, allowing for easy targeting of enemies at long range. However, there are still differences in ADS spread between different weapons. Generally, assault rifles < submachine guns ≈ light machine guns < shotguns. The lower the ADS spread, the higher the hit expectation at medium and long range, increasing accuracy for tracking moving targets and shortening the expected TTK at these distances. This precision difference caused by random spread cannot be reduced through muscle memory actions like recoil control or tracking. Because of this parameter, light machine guns have always been a somewhat awkward presence in COD multiplayer. Their inherently slow ADS time and longer effective range suggest they should be used for defensive holding point gameplay, but their ADS bullet spread is larger than that of assault rifles. If not relying on crouching or prone positions to reduce random spread, they might actually have a lower hit rate, making them less effective than assault rifles and sniper rifles. However, in a high-precision shooting game like COD, maintaining a crouched or prone position, which involves slow movement, significantly increases the enemy's hit rate, leading to a disadvantage for light machine guns. This generation introduced a mounting system that allows for reduced random spread and lower recoil while standing, without losing the flexibility of quick movement, significantly improving the practicality of light machine guns.
Other Secondary Attributes:
Finally, there are some secondary weapon attributes that also play a role in differentiating the shooting experience. These attributes provide unique balancing methods beyond the two core balancing principles mentioned earlier. If a weapon is strong in both its TTK performance and in offensive/defensive play, it will certainly have weaker performances in some of these secondary attributes to maintain balance.
Body Parts Damage Multiplier: The random spread of a weapon affects the expected TTK. Directly linking these two parameters through possibility in missing the enemy would result in a poor gameplay experience. However, by assigning different damage multipliers to body parts such as limbs, head, upper and lower body, etc., overall spread can be kept small. Weapons with relatively poor spread can still not miss the enemy, but they may hit lower-damage areas like the limbs, resulting in a longer actual TTK. This, in my view, is a very clever design, consistent with the previously mentioned design principle of "immediately rewarding the player's correct actions."
Bullet Types, Penetration Performance: Bullet type affects the ease of picking up ammunition on the battlefield, while penetration performance affects whether bullets can penetrate cover in certain combat scenarios, causing damage. This design must conform to the real-world calibers used by the weapons. After determining the penetration performance of different calibers, the player's combat experience is controlled by the penetrability of cover in map design.
Magazine Capacity: Affects the margin for error in simultaneous multiple engagements or long-range combat.
Movement Speed: Roughly related to the actual weight of the weapon, faster movement speed offers higher survivability and is more suitable for fleeing or rushing.
In summary, the core weapon value balance in CODMW relies on the following two principles: the counterplay relationship divided by TTK advantage distance, and the enhancement of advantage distance through ADS performance and recoil characteristics.