Inventory Systems

A well designed, simple inventory system can greatly improve a player's enjoyment of a game. This is especially true in games where players must frequently change their character's equipment to adapt to situations in the game, such as the Resident Evil series. So why do so many games design their system so poorly?

Here are some requirements for a good inventory system.

1. The inventory must be able to easily hold the items that are needed for regular use in the game. This includes things like weapons, ammunition, healing items, and especially plot items. If you do not have sufficient room for these "must have" items then the player certainly will not have room for other items that are of only situational value. You can certainly have a limit to how much stuff a player can have in their inventory, that limit just needs to be set with a realistic look at how much stuff players HAVE to haul around with them to be able to play the game.

For a game that does this well, look at Baldur's Gate II. You can have a party of up to 6 characters, each holding 12 items, in addition to three slots for weapon ammunition and three quick slot items (which can be magic scrolls, potions, and other consumable items) per character. Additionally, weapons and armor that are equipped on the character are not stored in those slots, they are put on the character's actual body. This system provides easy room for all of the needed items, allowing the player to use the remaining 12 slots per character for situational and plot related items. Additionally, the game offered some items, such as bags of holding, that could hold 20 or so items each, freeing up additional room.


The inventory system of Baldur's Gate

The game frequently requires players to hold on to items for a long time until the party can find a town to sell them at, so all of the inventory space is extremely useful. However, there is still depth to the system because even with all this room there are still many situations where players will need to decide what they want to keep. Additionally, items have weight so players need to balance where they put the suits of plate mail.

A game that executes this extremely poorly is Resident Evil 5. In this game, players have two characters with only 8 slots each that they can put items in. Every weapon takes up a slot, armor takes up a slot, every healing item takes up a slot, ammunition takes up a slot. So, if you want to have armor and three different guns, you only have one slot available for healing items. Additionally, the method for exchanging items between the two characters is extremely cumbersome when both inventories are full. This system makes the player frustrated when trying to strike a balance between necessary healing items and necessary weapons/ammunition.


The ridiculously small inventory of Resident Evil 5

2. Make the inventory easy to organize. In systems where items are stored in a long list, items that are used in combat, such as healing potions, should be at the very top of the list. This makes them easy to access when they are needed in a hurry. Ideally, the system should have options available to have the computer auto-organize the inventory for the player. This minimizes time spent moving items around on various menus to make room for the new sword that the player just found.

3. Pause the game when the player is accessing the inventory screen. There is nothing worse than being killed while trying to find a healing potion that is dug five screens down in a poorly designed interface. One exception to this rule might be that if the player is in active combat then it is fine for the game to keep running, to simulate the problems with trying to grab another weapon or something while you're in a fight. However, if the inventory is cumbersome this is not a good way to add tension to the game, you're only going to make the player mad.

4. Make the inventory menu large enough to easily see what you have access to. All of the Final Fantasy games do this extremely well. You have a lot of items, but the inventory screen fills the entire game screen so you can see everything in a few moments. Resident Evil 4 does this with skill as well. You have an attache case screen that shows all your weapons, ammunition, and such graphically and it only takes up one screen.

King's Bounty is a game that executes this extremely poorly. You have a screen with your character and below him you only have five slots with arrows on both ends to scroll through them. Unfortunately, every single item you pick up in the game, from armor to consumables, goes into this inventory and to use them you have to scroll through them one by one every time. This takes a lot of time and is needless-a separate inventory menu should have been created to ease this for the player.

5. Stop trying to represent item size in inventories by using grid based systems-such as making a battle axe take up 6x4 spaces. This is the method used in almost every action RPG-which is kind of funny because you end up being taken out of the action and trying to rearrange your items so you can pick up that new weapon you just got.

Have fun trying to fit everything in here!

It's much more convenient for the player to have a slot based inventory and let smaller items, like healing potions and magic scrolls, stack. Look at World of Warcraft for a decent system. If you must represent item size, use weight instead of grid hexes, as in Baldur's Gate.

There is one notable exception to this rule and that is in Survival Horror games. In these games, part of the tension is that you have limited resources in a hostile environment. In those cases, organizing your inventory actually adds to the tension because you have to consider whether every item is worth picking up. I'm low on shotgun ammunition, but I have to drop a healing item for it... is that worth it?

Resident Evil 4 had one of the best inventory systems I've seen for a game of this type. You have an attache case that you can spend money to upgrade to hold more items. This adds more strategy to the game because you can buy new weapons or improve those weapons, or you can spend the money to hold more stuff.


I'm not sure how Mr. Kennedy fits a rifle, a shotgun, a machine gun, and a handgun in this box, but it does work quite well with the game

With these five steps, every game should have a reasonably easy to use inventory system that minimizes the burden on the player and keeps the focus on the game, not on organizing your catalog of items.