That Which Is Not Forbidden: The Spectrum of Allowance

When Grand Theft Auto III came out, it introduced a new interaction to the series: players could now solicit prostitutes and then kill them to get their money back.

“To engage with prostitutes in the game, all the player had to do was pull up to certain scantily clad women, who would enter the vehicle in exchange for a sum of money. . . . Disturbingly, players found they could reclaim their cash by simply killing the prostitute with their car after she’d exited."
—Samantha Leichtamer, The 5 Most Shocking Grand Theft Auto Moments

This capability persisted in later games in the series and gave rise to a lot of discussion. Much of the commentary was careful to point out that murdering prostitutes is not required at any point. But of course Grand Theft Auto games are exactly that: games. You don’t have to play them at all. And they’re known as games where a lot of the fun comes from messing around in the sandbox, going on murder sprees that are also thoroughly unrequired. So is there a meaningful distinction to be made here?

I think there is. Merely pointing out that you can do something in a game is incomplete. It treats it as a binary, with the action either allowed or disallowed. But game design is much more subtle than that. There’s a wide range of how allowed an action can be.

The Spectrum of Allowance

Impossible Prevented Ignored Emergent Punished Acknowledged Enabled Rewarded Core Required

Here’s the spectrum as I see it. On the far left are actions which are completely disallowed. The degree to which the action is legitimized or encouraged by the design itself increases to the right, until on the far right we find actions which are full-on mandatory.

Let’s take a closer look at each section of the spectrum.


The action is outside of the game’s design scope.

Most actions are out of scope for most games, as any individual design must necessarily define a small portion of the space of all possible designs. In many cases, this is a good thing. It allows games to be more thematically unified and enjoyable, and most impossible actions go totally unnoticed. It’s probably for the best that you can’t attack the villagers in Animal Crossing or challenge opposing team members to chess matches in Overwatch, for example.

In other cases, impossible actions can feel like glaring omissions. This is especially likely if the actions were considered for inclusion but cut for budget or schedule reasons or simply rejected as a design choice. Many players wanted to be able to trade items in Destiny, for example, but there is no way to do so. Alternately, impossible actions can be a form of railroading - it frustrated many players that there is no option to avoid working with Cerberus in Mass Effect 2.


The action is actively disallowed by the game.

In these cases, the action is within the game’s scope and you would be able to perform it if the game didn’t specifically account for it. But for whatever reason, the designers have chosen to forbid it. This is often done to enhance a game’s thematic coherence or to avoid particularly abhorrent possibilities. For example, Crazy Taxi prevents you from running over pedestrians, as they will always dodge if the taxi gets too close. Violence to children is very commonly prevented - for example, in World of Warcraft you can attack most opposite-faction NPCs, but children can’t be targeted or damaged.


The action has no effect within the game’s universe.

The action can be performed, but the game doesn’t react to it in any way - the state of the world is just as if you hadn’t done the action at all. This often happens naturally in any sort of social interaction due to the limitations of NPC AI - for example, in basically every action game ever you can walk up to an NPC and start jumping up and down in front of them and they won’t react to your bizarre behavior in the slightest. But it can also happen in physical interactions - for example, in Duck Hunt you can shoot the dog however many times you want, but it won’t stop laughing at you for missing the ducks.

This is often a good way to handle actions that are absurd in-universe. It may seem realistic and immersive to have NPCs comment on your bizarre behavior, but in many cases bizarre behavior is the unintentional result of struggling with limitations of the interface or simply remembering which button does what. If the game ignores these behaviors, so can the player; if the game reacts to them, it actually damages immersion by separating player intent and character action. (See Dara O’Briain’s classic bit about Metal Gear Solid for a send-up of this idea.)

Note also that this is the best way to discourage players from taking particular actions. An ignored action is an uninteresting one. As Jenova Chen put it when discussing design lessons from Journey, “If you want to teach players not to do something, you don’t need to smack them. You need to give them zero feedback.”


The action is a natural extension or interaction of other mechanics, and the game responds to it in a way consistent with the normal handling of those mechanics.

The more “systemic” a game is - the more its interactions are the result of rules rather than scripted events - the more emergent behavior is possible even if not explicitly designed for. For example, in The Legend of Zelda: Breath of the Wild, metal equipment conducts electricity. This can result in you getting struck by lightning if you’re wearing metal armor and waving a sword around in a storm. But since unarmed enemies will pick up weapons, this also means you can toss a weapon to an enemy and trick them into getting hit by lightning instead. And since some puzzles involve completing electrical circuits, you can skip them by laying down a path of metal weapons to conduct the electricity across the gap instead.

Note that an action being emergent doesn’t necessarily mean the designers were unaware of it - just that it didn’t have to be explicitly designed for or coded in. Once the designers are aware of such an action, choosing to leave it untouched instead of adjusting it to be prevented or ignored is an active design decision that implies tacit approval.

For example, in The Elder Scrolls V: Skyrim, you only get in trouble for crimes if there is a witness, and lines of sight are blocked by solid objects. Shortly after the game’s release, it was discovered that you could block a shopkeeper’s vision by placing a bucket over their head and then steal everything from their shop without getting caught. Whether to make a change here was an open question for the developers.

“It was like day two, and we went, what? Do we fix that? Our lead programmer is pissed and wants to fix it, and I said I’m not sure we should. That’s one of those where maybe we leave it in."
—Game Director Todd Howard, as quoted in Skyrim to have multiple DLC releases, powerful buckets

The way a game’s player base reacts to an emergent action can also change the way the designers see it. In Super Smash Bros. Melee, certain physics interactions meant that if you knew the right maneuver, you could slide rapidly along the ground while performing attacks that normally require standing still - a technique that has been dubbed “wavedashing”. Creator Masahiro Sakurai noticed this capability during development, but he didn’t expect it to have much impact on gameplay so he left it in. Once the competitive community discovered it, however, it became all but required at the tournament level. Sakurai disliked the limits this placed on playstyles and the way it magnified the gulf between new and experienced players, so in subsequent games the physics have changed and wavedashing is impossible.


When the action is taken, the game responds in a way that mechanically discourages the action.

Performing the action makes the game’s goals or win-state harder or impossible to achieve. In extreme cases, it’s an instant failure state, such as for killing too many civilians in Assassin’s Creed games or shooting certain friendlies in Call of Duty games. In other cases, it handicaps the player in some way. For example, in The Legend of Zelda: Link’s Awakening, stealing from the shop will get you renamed “THIEF” and cause the shopkeeper to kill you if you return to the scene of the crime.

Note that punished actions are more permitted than ignored ones. Actions that cause no consequences don’t feel like they really happened. Responding to an action - even in a negative way - legitimizes the action by making it something you can meaningfully do in the game’s world in a way that is clearly deliberate by the designers.

For example, a personal anecdote: In Star Trek: Voyager - Elite Force, you can’t kill your squadmates but if you shoot them they will complain. When I realized this, I got curious and kept shooting them. Eventually, they shot back and killed me - and when I experienced that, I felt awful. It was a bad thing and it actually happened and I was the one who did it. By comparison, in Mass Effect, shooting your squadmates has no effect at all. When I realized this, it barely even registered and I just moved on with the game.

Sufficiently extreme or unusual punishment can also function as an Easter egg. Maniac Mansion famously lets you kill a hamster in the microwave and show the remains to the hamster’s owner who kills you in revenge. Many Zelda games have chicken-like animals called Cuccos which are normally docile, but if you attack them they summon a deadly flock that swarms you unless you can get away in time. Both of these are in-jokes in their respective fandoms and have been reused, referenced, or modified in subsequent games.

Even mundane punishment can be used for an extra challenge:

“Black Desert [Online] allows you to opt-out of PvP. However, players can still attack you, even if you’re flagged as not willing to participate in PvP. . . . [T]he penalty is that [the attacking player] will get negative karma. . . . This is, of course, a monumentally stupid system if your actual goal is to protect players who don’t want to PvP. Aggressive and challenge-seeking players will naturally want to know about what the ‘challenge’ of negative karma looks like, which means you’ve just created an incentive for griefers to kill players who have explicitly said they don’t want to participate in this dumbass open-world deathmatch. Some players enjoy the added challenge of running around with negative karma and being attacked by town guards. . . . [T]he developers made this convoluted system where the game allows you to do something and then tries to punish you for it, thus sanctioning that action as a valid form of gameplay."
—Shamus Young, Black Desert Online #4: The Final Straw

I’m going to harp on this a little bit more: punishing an action sanctions it as a valid form of gameplay. It turns it into a deal - if the player does X, the game will do Y. The player can weigh the tradeoffs and decide if it’s an exchange they want to make.

It’s the same principle behind the infamous day care late pickup fine backfire. A day care center attempted to encourage parents to be on time by imposing a fine on late pickups - which resulted in an increase in late pickups. The fine turned lateness from a violation of a social norm into a valid purchasable option and parents frequently found it worth the cost.

If you don’t want players doing something and you can’t prevent the action itself, prevent its effects by ignoring it. Don’t punish it. This isn’t often an option in the real world - the day care workers couldn’t simply refuse to let parents' lateness waste their own time - but it is in games' designed worlds.


The action is a natural extension or interaction of other mechanics, and the game responds to it in a special and unique way with no mechanical effect.

Acknowledged actions are similar to emergent ones, but since the game actually responds it’s clear their inclusion is deliberate. The action is thus implicitly approved without even the mechanical penalties of punished actions. This is true whether the tone of the acknowledgment is positive, negative, or neutral. For example, in Deus Ex, it’s possible to enter your office’s opposite-gender restroom. If you do so, your boss chides you for it later. And in Wii Sports, it’s possible to roll the bowling ball backward - which causes the assembled crowd of Miis to jump and shout in surprise. This kind of unique reaction is often considered an Easter egg and the curious player is likely to seek it out.

Even without any mechanical reward, just giving the player a unique response indicating their action was noticed is an incentive. The Warcraft and Starcraft games acknowledge repeated clicks on friendly units by having the units start complaining, and I certainly recall obsessively clicking on each type of unit to find out what it had to say. Acknowledgment can also be a way to reward actions that are unnecessary but quite difficult to perform - Metroid Fusion acknowledges a difficult sequence break by displaying a unique message praising your skills and wondering how many players will see it.


The action serves no mechanical purpose but is explicitly allowed for by the game.

These actions are not emergent results of other mechanics, but had to be specifically and deliberately added to the game’s design. For example, Assassin’s Creed III allows you to pet dogs and other animals you come across, which has no effect besides the animation of doing so.

Common use cases include social interaction (emotes in World of Warcraft, taunts in Team Fortress 2) or player expression (photo modes in games like inFamous: Second Son or Super Mario Odyssey). Enabled actions can also add extra realism - a surprisingly high number of games include pointlessly interactive bathroom fixtures.


When the action is taken, the game responds in a way that mechanically encourages the action.

Performing the action makes the game’s goals or win-state easier to achieve. For example, in Ratchet & Clank games, destroying environmental objects such as light fixtures and display screens rewards you with bolts, the in-game currency for buying weapons and ammo - though generally fewer than you’d get by killing enemies instead.

This is a very clear-cut way to encourage particular behaviors without making them necessary. It can also be used to allow flexibility in how a player approaches a game. In Saints Row games, a wide variety of actions are rewarded with “respect” (called “XP” in later games). These include highly-structured activities like completing side challenges and finding collectibles and less-structured ones like combat and driving stunts. Respect is then used to unlock story missions in the early games and upgrades in the later ones. This means you can choose between any of the respect-rewarding actions and still progress in the game, so players with varied playstyles are more likely to be able to play in the way they enjoy.


The action is one of the central mechanics of the game.

The action is featured prominently in the game. It’s taught to players early and gets mentioned when the game is described in conversation or marketing. For example, jumping on Goombas in Super Mario Brothers or picking up new abilities in Metroid.

In these cases, the game is designed around the action. You aren’t just encouraged to perform it - you’re expected to. Playing the game without doing so is a self-imposed challenge for the hardcore - for example, “pacifist runs” are kill-free playthroughs of games where combat is a core mechanic.


You cannot complete or proceed in the game without performing the action.

The action must be completed in order to progress in or beat the game. This can be a repeated mechanic, such as interrogating people in L.A. Noire, or an isolated instance of option restriction such as entering the lighthouse at the beginning of Bioshock.

Required actions are the flip side of impossible ones - an action being required means that avoiding that action is impossible and vice versa. As such, required actions can also railroad the player - in the beginning of Fahrenheit, you must leave the diner in order to avoid failure and proceed to the next scene of the game.

Having all this defined should make it easier to speak clearly about Grand Theft Auto’s murder-based prostitution refunds. (Leaving aside for the moment any judgments about the appropriateness of the design, the moral culpability of the designers, or the social value of Grand Theft Auto in general.) Soliciting prostitutes is a rewarded action, since it restores health. Killing people in general is a core action, since it’s one of the most common and centrally-positioned interactions in the game. Money-tracking was specifically coded in and enabled, but since the only way this manifests to the player is that they can get back spent money by killing the person they gave it to, that makes killing them also a rewarded action that restores money.

Combining all of these, getting your money back by killing a prostitute is an emergent action. On an allowance level, it’s the same as buying food from a vendor (which also costs money and restores health) and then killing the vendor to get your money back. There’s no reason to think it was specifically designed into the game as opposed to just being one of many implications of the interactions of other mechanics. That’s the point people made when discussing it. But while it’s plausible that the ability was unintended in Grand Theft Auto III, the developers are certainly aware of it after the controversy it generated. Leaving it in later games rather than preventing it is clearly deliberate. They want the player to be able to do it.