This is the summary of our podcast episode: Episode 1 – Inventory Management
History of inventory management in video games
For as long as our characters have needed somewhere to hold or store their equipment, there has been an inventory system in video games to represent this. How these systems ought to look and function is of course therefore an important design choice. Yet for a game concept as ubiquitous and central as a character’s inventory, it is surprising how non-innovatively it has been approached through the years.
Indeed, already in the late 80s and early 90s, inventory systems consisting of a simple list (sometimes limited by number, weight or copy of items) were relatively common. During the 90s, an early form of physicalization of inventories into equally or differently sized icons (sometimes likewise limited by weight) arranged in a grid system became commonplace. These two forms of representing what our characters are carrying remain to this the day the most common in video games. The Witcher 3’s (2015) inventory differs relatively little from that of Diablo (1996), or indeed Dungeon Master (1987). Equally, the list of items held by our heroes in Skyrim (2011) or Fallout 4 (2015) mirrors that of Heimdall (1992) or Ultima 5 (1988).
More modern inventory systems
A more modern take on the inventory system is the perhaps paradoxically more limited one manifest in e.g. the weapons management of Mass Effect 3, The Last of Us or Red Dead Redemption II. Each of these games feature properly physicalized and rendered positions and holsters on the character’s body for storing weapons, and each position can hold exactly one weapon of the correct type; if you pick up a new one you must leave behind what used to be there. This idea of not being able to stock up on weapons in the manner of e.g. the gunwheel of Grand Theft Auto V was explored thematically in Mirror’s Edge and Superhot where guns only served as temporary, yet clearly physicalized, possessions and could not be stored in an inventory.
In these games, this design choice synergised and reinforced the style, feel and narrative and as a result greatly enhanced players’ immersion into the game’s world and setting. To have had our runner protagonist in Mirror’s Edge horde weapons, for example, would have diminished the sense of urgency and vulnerability that pervades and defines the experience of the game.
So the above mentioned more restricted, and perhaps more realistic, take on inventory management, where items are genuinely physicalized and more truthfully limited, generates the effect of both reinforcing the realism and believability of the game’s world and setting, as well as enhancing player immersion. The Last of Us, in particular, does this extremely well by integrating animations not only for swapping weapons as in Red Dead Redemption II into actual gameplay but also physicalizes, animates and thus realizes the process of crafting items into genuine gameplay where our protagonist Joel will kneel down and fiddle in his backpack while creating new items. This process maintains the emotional and narrative connection between player and character by avoiding non-gameplay menus and grids.
The competing demands on inventory systems in video games
While limiting items in a player’s inventory in this way serves the purpose of building immersion, item limitation itself also serves many other functions regardless of inventory system used, be it list, grid or physicalized. Characters’ inventories also act as the mechanic exercising control over the number of different equipment options a player has at their disposal at any point in time as well as potentially the strength of this equipment; a player’s ability to store more, larger or heavier items may unlock more powerful abilities or skills. This means that a game’s inventory system is therefore at least partially also responsible for managing the flexibility and power curve of players. Furthermore, as soon as a game includes any form of commerce system, the inventory naturally becomes an integral connection between the player and the game economy. Thus the inventory system is also responsible for managing this aspect of the game.
This diversity of functions and responsibilities places competing demands on the inventory system of a game. The challenge of balancing these different demands is at the core of why so many games end up with poorly-aligned and frustrating inventory management.
Carrying capacity and loot
An example of these competing demands is inventory weight capacity limiting both the number of different equipment sets a character may carry (i.e. heavy armour, shield and sword as well as lighter armour, bow, and daggers) as well as the amount of loot or treasure they can bring with them to sell or trade along the way. The idea of limiting the equipment a character can carry is in part to force the player to commit and adopt a position along various trade-offs. You can’t have every kind of weapon and every set of armour with you at all times because then your gameplay experience will be full of simply swapping these to adapt to the situation as well as a lot less dynamic as you will face all problems with the perfect equipment available. From this perspective of course it makes sense to limit how much a character can carry.
However, when the function of the inventory system is also to manage the players’ economy by facilitating trading of looted or gathered items then this carrying limit becomes problematic. Of course there is an element of realism to not being able to carry an infinite amount of items, yet the number of suits of armour a character can carry in e.g. Diablo hardly adheres to this realism. The question then is why is your inventory limited at 40 slots in Diablo? Why not 60 or 80 slots? In terms of realism, it’s still preposterous to carry that much equipment, after all. Of course the answer is so that players won’t be able to carry such a wealth of diverse equipment that they have the potential to be perfectly adapted to every situation that may arise.
Unfortunately, a consequence of this 40 slot limit in Diablo is that it also dictates the frequency with which players need to return to town to sell their looted items. The same is true of the Elder Scroll games, where the weight limit dictates the frequency of players needing to return to a merchant to sell stuff. While this frequency can be integrated into a game’s narrative, such as by creating various events that occur near these merchants that the player will experience in conjunction with selling items, more often than not what happens is that trading and selling loot becomes the closest thing to a chore in a game.
While Divinity: Original Sin II cleverly integrated bartering into the game by allowing players to trade with essentially all NPCs, it is still true that the balancing of carry limits and organizing recovered items to be sold became a painful experience in terms of inventory management. The Torchlight games innovatively approached this problem by introducing a pet who acts as an agent of trade for the player, carrying looted items to town so that the player may focus on the more enjoyable aspects of gameplay. Sadly, few other games have followed suit with similar or indeed alternative mechanics to resolve this issue.
Immersion, the economy and intended power curves
Another problem resulting from the competing demands placed on the same inventory system is the issue of a player’s wealth, and by extension power. In many games a character’s power is related to the equipment they carry, which is frequently measured in terms of a financial value. Because most games are designed with a power curve in mind, i.e. the trajectory of increasing relative strength that players will experience throughout the course of the game, it is important for games to be designed in such a way that players cannot immediately or quickly gain access or possession of powerful equipment that would elevate them beyond their intended position on this curve.
When equipment is potentially available through a game’s economy it therefore becomes important for developers to restrict too rapid economic growth. This is often achieved through mechanisms such as limiting the amount of money merchants and traders have at their disposal, introducing restrictive carrying capacities in terms of weight or slots in a grid system as well as restricting the number and amount of items that are lootable in game, thus slowing a player’s economic growth.
However, this combines poorly with games’ efforts to build realism or to immerse their players into the game’s world and setting. For example, it becomes harder to maintain the suspension of disbelief needed to truly sink into the world of The Witcher 3 when you reflect on the fact that our protagonist Geralt, despite being in need of money to finance the acquisition and improvement of equipment, frequently discards or at least ignores clearly rendered items that are established in the game setting to have value such as swords, armours, etc. Given the setting designed and established by the game, it does not make any sense for Geralt to act in this way and we as players might rightfully question the coherence of the game world.
So immediately, believability and consequently player immersion suffers because, again, the inventory system is trying to fulfill two contradictory aims; namely both to represent our character’s interaction with items in the world as well as limit our potential economic and power growth. Why doesn’t Geralt collect more readily observable materials and equipment from vanquished foes, seeing as they are clearly valuable?
On the other hand, a poorly aligned economy and inventory system can also go the other way. Kingdom Come: Deliverance purports to offer the player a believable medieval experience of a lowly peasant, which it of course triumphantly does in many ways. However, part of the realism for which the game was explicitly designed leads to you being able to steal and loot essentially everything you can see in the game. This means that it is not particularly difficult to relatively quickly in the game get the upper hand on a lone knight and claim their extremely valuable equipment or rob a very wealthy merchant and steal their riches.
In a sense, this is of course realistic, and succeeds in maintaining the believability of the world and consequently player immersion. However, it robs the game of the experience it had set out to offer; namely, that of a lowly peasant cast into a violent world suffering at the whims of richer, wealthier and better equipped lords and knights! Kingdom Come: Deliverance suffers not from the unrealistic loot and inventory management of The Witcher 3, but instead of perhaps too realistic an economic simulation in which the intended power curve, designed specifically for this game and its narrative, can be completely ignored by the player netting a suit of plate armour or chest of gold on their second day of life in medieval Bohemia.
Here, again, the game is suffering from the inventory management system trying to fulfill mutually exclusive aims; to both realistically and immersively simulate medieval society but also to pace and manage the player’s development along a power curve with the game’s narrative in mind.
The scavenging economy
Indeed the marriage of inventory management and game economy is an unhappy one. Another extremely common, surely unintended, but consistently overlooked effect of an inventory system being subjected to these competing demands is that players are reduced to scavengers, salvagers and hoarders of iron daggers, valuable scrolls and precious stones, rather than the adventurers and heroes their characters are in the game. The defining features of interest of an item are no longer its origin, function, history or even statistics in the game – it’s the scavengers’ ratio of gold:weight. Perhaps the most obvious example of this is the Elder Scrolls series, where a common player experience is to relatively quickly become fantastically wealthy by making sure to loot, transport and sell or barter away everything they can possibly beg, borrow, steal or claim from the get go.
Games have attempted to approach and resolve this problem in a number of ways, through mechanics such as gold-capped merchants (e.g. Mount & Blade and Divinity Original Sin 2) or introducing a mechanic that heavily slows or completely prevents your movement when carrying over a certain weight or amount of items (e.g. Skyrim and Kingdom Come: Deliverance). But these mechanics only serve to frustrate and annoy players and act as a hindrance to their attempts to execute what is clearly the optimal strategy given how the game is designed; namely to fully loot and scavenge everything for monetary gain.
To be clear, this is occurring because the inventory system employed in the game is trying to fulfil two distinct and contradictory aims – to both manage a player’s wealth and possessions, and to manage a their power curve, which is, after all, strongly tied to the equipment and items they possess. Because of the way games often are designed, clearly the best economic strategy is to collect and sell everything possible. But game designers generally do not want players to do this as that would speed their progression beyond what makes narrative sense. Yet instead of redesigning games to create an experience where the optimal strategy is more aligned with their intended progression curve, game designers frequently employ additional mechanics to hinder players in their attempts to maximise their income, such as the movement speed reduction or merchant gold limitations mentioned above.
Our analysis is that the problems and dissatisfaction frequently surrounding inventory management in video games stems from competing non-aligned demands placed on the system as a result of poor design choices. For example, having an inventory system both function as a tool to immerse players into the game world as well as manage their power curve through the course of the game forces developers to make sub-optimal design choices relating to either or each of these functions. Four commonly assigned functions to the inventory system are presented below as well as the demands placed by these functions on two aspects of inventory management; inventory size and access to items.
|Game aspect||Inventory Size||Access to items|
|Power curve & economy||Restrict to control growth||Restrict to control growth|
|Trade-offs & strategy||Restrict to limit options||Variable|
|Looting & trading||Expand to facilitate trading||Expand to enhance trading|
|Believability & immersion||Restrict to maintain realism||Expand to include observed|
The function of controlling the economy and by extension power curve of a player is exercised through limiting both inventory size, e.g. through carrying limits, as well as access to items, e.g. by making not everything present in the world lootable. When inventory management interacts with intended tradeoffs in the game, players are prompted to adopt a certain strategy or decision by restricting their inventory size such that they cannot equip themselves with all possible items and hence must select one strategy among many competing ones. In terms of access to items, increasing access yields greater variety of strategies yet simultaneously reduces the commitment of players, who, after all, may find the equipment they turn out needing in the game world by chance.
Naturally, for the function of trading, the inventory system ought to consist of both sizeable storage and rich access to items, lest this component of the game be unfulfilling. Finally, believability and immersion is maintained via the inventory system of a game by limiting inventory size while granting access to any items feasibly available in the game world.
It ought to be clear from the above that these functions are clearly not aligned and any game designed with the intent of fulfilling all these competing aims will surely suffer for it. A game that manages to unify their aims and goals is a more cohesive and enjoyable product and thus the decision to include an inventory system in a video game should not be made per default, as it seemingly is today. Rather it should be carefully and thoughtfully crafted so that it integrates and makes sense with the game’s broader narrative or intended experience. Looking back over the past three decades of video games, it seems that the rule has been to include an inventory system without properly considering this design choice, and only as an exception do games release with thoughtfully, carefully and holistically designed inventory management.