Uncharted 4 : Systemic Combat

In his GDC talk, Matthew Gallant (combat designer at Naughty Dog) discusses how for Uncharted 4 the combat team reevaluated how they approached combat design. Instead of tightly scripted encounters, the game moved towards a more systemic approach to NPC AI behavior. Today I'd like to examine the player experience that flows through from this approach and how it relates to the underlying system.

COMBAT ROLES

• Inspired by Pacman's Inky, Blinky and Pinky, Uncharted 4 has 3 combat roles in the game :


1. Engagers - Close in on player position.
2. Ambushers - Pick an ambush point and hold their ground. As the player gets closer, they pop out and surprise players adding tension and making the place feel fuller.
3. Defenders - Assigned to hard points where they hold their ground and fire. This gives the player focus points to navigate towards.
   

 


• The assignment of these roles are systemic and based on a set of global parameters.
  
  
  
  
  
• But ofcourse the player is unaware of this internal system. So how does this system translate into a player experience?
• The player's mental model of a combat arena (when in an active state of combat, i.e., not sneaking) is quite simply an internal priority list for who to fire at. Below are some of the factors based on which this prioritization occurs :

1. Damage dealing ability
2. Distance from player
3. Jeopardy to current position
4. Maneuverability to next cover position or vantage point

• The key to the nature of these global params is to accommodate for the ability to break the player's mental model in incremental steps.
• For example, the engager count and time delay to replace an engager result in an NPC dynamically becoming an engager when an NPC is killed. This essentially invalidates the player's established next steps but in a manner that she can clearly react to.
• The params also need to be constructed in a manner that the player is incapable of predicting the reaction of the system to her actions.
• Therefore, the resulting experience from this system is one of constant re-prioritization where the player is constantly reacting to systemic changes.

DIFFERENTIATION FROM THE LAST OF US

• In TLOU, due to the instant death nature of contact with clickers the player is expected to formulate a strategy for as large a window as time as possible.
• From that point onward, gameplay revolves around deft execution of that strategy through timing.
• The player is expected to react at points where she fails to execute on a given strategy or when the strategy has failed to accommodate certain aspects of the layout.
• However, the result is to scramble to safety and reevaluate. In this manner player's are much more constrained than in Uncharted, in two ways :

1. In UC planning is only incentivized not enforced. 
2. In TLOU, reactions are high pressure break points from game flow. In UC, the player is in a constant reactionary state.

• However, the tight constraints in TLOU, implies that situations where the player is pressured into breaking free from these constraints are meaningfully differentiated and create a tension that Uncharted's systemic combat can never achieve.
  

SYSTEMIC AUTHORSHIP - ILLUSION OF AGENCY

• In the talk, Gallant also makes the assertion that it was important to the design team to be able to continue to exert a controllable degree of authorship over each encounter. I'd like to examine how systems can accommodate for such tight authorship when required.
• The solution is heavily dependent on level design based indirect control. I think it is safe to say the more vast the encounter space, the harder it is to author.
• For example, consider the following encounter (Reunion) :
  
  
• From the player's perspective this may seem like a pretty open space at first glance. However, there are really only two arteries that run through this space. It roughly corresponds to the following layout :

• The furthest defender is an RPG wielding bad ass so he's pretty much your directional indicator. The natural behavior from this layout is to use one of the first two cover points to get a better layout of the land.
  

 

• At this stage, the player is forced to choose one of the two arteries that cut through the level. However, the game employs a few tricks to force the player into the decision it wants her to make, i.e., select the elevated path :

1. Each of the cover points are destructible forcing the player to shuffle right, i.e. towards the "right" path.
2. Incoming engagers and defenders reinforce the decision to go right to gain additional cover.
3. The nature of the layout is sufficiently clear for the player to decipher vantage ability.

• Once the player has climbed onto the ledges, the game is now poised to counter the player with tailored scenarios made possible systemically. For example :
• The player hanging on the ledge triggers an ambusher setting the player up for an over the ledge gun shot.

   

• Similarly, the player jumping thresholds triggers ambushers on a different vertical axes as shown below. Additionally, killing the ambusher allows the defenders to be reassigned to engagers further pressing the player to utilize his vertical vantage.
  

      

Destiny : Through the Lens of a Single Player Game

In his GDC talk, Justin Truman from Bungie mentions that one of the goals for Destiny was to make a multiplayer game that had all the juice of a single player FPS. In this blog, I'd like to look at the moment to moment gameplay that creates this juice. Zooming this lens out a bit more, I'd also like to look at how Destiny 's features reflect or contradict some of the larger trends in the FPS genre. These trends are explained brilliantly in Justin's Pierce's Gamasutra blog here.

THE ZEITGEIST OF FPS

In his blog, Justin argues that the paradigm shift from PC to console and therefore mouse based input to controller based input is the root cause for changes in minute to minute gameplay.

                

                Higher Range of Motion                                   Lower Range of Motion

Essentially because the range of allowed input is greatly reduced when moving from free form mouse movement to thumb based joystick rotation, games slow down combat so that it's easier to track targets using a controller. This then necessitates mechanics such as sprinting to speed up non combat situations, aim down insight for targeting assistance, and OP melee attacks to counterbalance being flanked in close range by charging enemies. Now digression aside let's return to Destiny.

DESIGN PILLAR - COMBAT TENSION

One of the cornerstones of Destiny's combat system is a sense of tension. This tension is largely elicited by keeping the player on her feet at all times. It's neither enjoyable nor possible to be successful in a Destiny encounter if you're camped in a location trying to take out enemies one by one. The indirect control over player motion is governed largely from the relationship between player and enemy attack ranges.

PLAYER vs RANGED

Both the player and enemies have ranged and melee attacks. However, the player will spend most of her time in ranged vs ranged combat. As in most ranged vs ranged combat, the player selects a suitable cover point and alternates between firing and retreating into cover to recover health.

Player vs Ranged Combat - Default Play Style

PLAYER VS MELEE

By establishing a default play style mode of sorts, the game then puts itself in situations where it can surprise players by breaking pattern. Melee attackers are used more as a tool to break player flow. Therefore, by simply modelling of context, the game greatly magnifies perceived danger. In most case, the player could simply hold their ground and execute a melee attack (which is typically high impact as Justin Pierce predicts). However, in most cases incoming melee attackers forces player backwards (out of cover) and requires her to reorient to the situation.

Player vs Melee - A Magnification Tool

EMERGENT COMPLEXITY

Establishing ranged and melee enemies in this way also allows the game to establish the difficulty of an encounter to be greater than the sum of it's parts. For example, placing an enemy with high damage ranged ability with waves of melee attackers forces players out of cover periodically exposing them to greater damage risk from the ranged attacker. This forces the player to think about enemy prioritization in terms of distance, impact to cover etc.

Two Ranged and One Melee Enemy 

Likewise, this perceived risk can also be mitigated by enemy zoning. Flanking players can create a heightened sense of danger and challenge. However, even though the perception is that she is fighting the enemy on all fronts really the danger is only from one set of enemies at a time because they have been demarcated to certain bounds.

TRIANGULARITY

The ranged - melee interaction systems also scales to different play styles based on risk taking appetite. Slower or weaker enemies can be slowly chipped away from behind cover or rushed and meleed aggressively.

Goblin - A Slower Moving Enemy

Other instances of high risk, high reward systems are heavy ammo, blaster and super attack systems. While almost all of the player's attacks are hitscan based, these are noticeably projectiles. To maximize probability of success this needs the player to break cover, get to a suitably close location, and then execute the attacks.

                

INCENTIVIZING RISK

Establishing high risk, high reward systems however only establishes support for different play styles. To encourage certain types of play behavior separate mechanics are required. Essentially the player needs an escape mechanism, when a high risk plan looks like it may go awry. In Destiny, the double aerial jump serves this purpose (which also serves as an innovative faster traversal mechanism as Justin identifies in his blog).

Double Jumping - An Exit Route

WEAPONS GALORE

Another means through which Destiny supports different play styles is by providing an arsenal of weapon that are meaningfully differentiated. Additionally the game is balanced to ensure that dominant strategy does not emerge through the selection of certain weapon types. This type of differentiation allows the player to parse through the arsenal based on desire rather than optimizing utility. This also allows the player to seek specific weaponry and results in enhanced satisfaction when it is found.

COVER SYSTEM

And finally, another system that encourages risk taking behavior and free form movement is cover. Cover is non sticky so the player's transitioning through cover is uninterrupted. Conversely there is uncertainty involved in whether cover is fully blocking attack for the same reason. The level design is such that cover is always accessible within a few seconds of movement which means players are freely moving through locations as opposed to mastering location maps. This also allows the player a basis to prioritize enemies, i.e., enemies that invalidate cover take higher priority. Emergent strategies from this system are shuffling through cover to surprise enemies from the side.