Explainer

Inventory, weight, and the rucksack problem

What a soldier is carrying decides what they can do, which makes inventory a combat system. It is also the part of a tactics game most likely to become ten minutes of admin after every fight.

There is a reason this subject will not go away. In a game where a turn is a budget, weight is the purest cost there is: carry more and you can do less. X-COM: UFO Defense (Mythos Games and MicroProse, 1994) tied it straight to the soldier's strength, so a trooper loaded past what they could manage lost time units, and time units were the whole game.

That is not an accounting feature. It is the same decision as whether to take the long flank: spend capability now, buy an option later.

The maximalist case: Jagged Alliance 2

Jagged Alliance 2 (Sir-Tech Canada, 1999) treats equipment as the second half of the game. Each mercenary has hands, pockets and a rucksack. Weapons take specific ammunition. Gear wears out and has to be repaired by somebody with the skill to do it, which means one of your hires exists partly to keep everyone else's rifles working. Carrying too much costs you the action points you needed.

The reason this is tolerated, and loved, is that every item is a decision with a consequence you can feel. Choosing between a second magazine and a medical kit is a tactical choice made an hour before the fight it decides. Underrail (Stygian Software, 2015) and Kenshi (Lo-Fi Games, 2018) run the same philosophy, and in Kenshi you can be carrying an unconscious friend, which is as physical as inventory gets.

The modern deletion

XCOM: Enemy Unknown (Firaxis Games, 2012) went the other way and took it out. You choose a weapon and a utility item before the mission and that is the end of the subject. There is no bag, no weight, no ammunition count to manage, nothing to pick up off a body.

As a reaction to busywork this was correct, and it is a large part of why that game is pleasant to play for an hour. But look at what left with it. No scavenging, so an enemy's weapon is not worth walking over to. No decision about what to leave behind, so no regret. No reason to fail a mission and still come home with something, which was one of the oldest and best feelings the genre had.

In a post-apocalyptic game that cost is much higher, because scavenging is not a system there, it is the premise. A wasteland where you cannot pick things up is a stage set.

Why it turns into busywork

The failure is specific and it is nearly always the same one: the decisions happen at the wrong time. If the interesting choice is which of two things to carry, that choice belongs before the mission or during it. What games actually make you do is sort through the aftermath, one container at a time, long after the tension has gone.

Grid-based bags make it worse by adding a second puzzle nobody asked for, which players call inventory tetris: not what to take, but how to rotate it so it fits. There is a reason that phrase is always said with a sigh.

The other failure is abundance. If a game gives you more ammunition and more supplies than you can spend, the whole weight system is theatre. Scarcity is what makes a rucksack a decision, and a generous game has quietly deleted its own mechanic while leaving the interface in place.

What the good compromise looks like

The arrangement that seems to work, across the games that get praised for it, has three parts.

A real loadout before the mission, with fewer slots than you want. This is where the thinking belongs.
Simple pickups during it. Ammunition, grenades, a medical kit, a better rifle off a body. Anything that takes more than one click is in the way of the fight.
Sorting after it that can be done in a batch, or not at all. If the player has to tidy, let them tidy everything at once, and let them ignore it without being punished.

Durability, the mechanic everybody is afraid of

Gear that wears out is the most unfashionable idea in this part of design, and it keeps earning its place. It makes a captured weapon a temporary advantage rather than a permanent upgrade, it gives a repair skill something to do, and it quietly stops the player hoarding, because a hoard decays.

It is unfashionable because it is annoying when it is cheap, which is to say when the only effect is a bar that needs topping up. It works when breaking is a real risk at a real moment and when the player could have seen it coming.

Where this leaves RAD Tactics

RAD Tactics is a squad tactics game for Windows, real time with pause, set after a collapse, with zombies and with factions fighting over what is left. It is in development, and we are not going to describe anything in it that is not finished.

The position the history argues for is clear enough: in a game about a collapse, picking things up has to matter, and nobody should have to spend their evening sorting the results. Those two are both achievable, and the second one is a user interface problem rather than a design one.