The immersive simulation genre is defined by a specific set of values, says Irrational senior level designer Steve Gaynor: they’re games in which you seamlessly inhabit an avatar, mine stories out of an exploration, grow abilities to become more capable in the gameworld, and become fully invested in an imaginary space.
"Immersion is a common buzzword in game development, but there’s a more universal term for it: It’s suspension of disbelief," Gaynor describes, speaking at the PRACTICE design conference at New York University.
"We can craft incredible places for our players to visit in plenty of different kinds of games… but in doing so, our foremost goal as designer should be maintaining the sensation that these places are real," he adds.
Games are defined by consistent sets of rules and patterns of behavior; one of the strengths of the human mind is that it’s adept at detecting patterns. Thus the rules need to maintain a naturalism that’s consistent and predictable – but not too much so – within the context of the game world.
The balance between systems and believability can be struck in the systems space, Gaynor believes. Designers build stories with a beginning, middle and end, and they’re designed to be experienced in order. Suspension of disbelief is broken when players are allowed to break that order, thus progression gating is necessary – however, too overt gating, or that which interrupts the naturality of the environment, also breaks belief.
"Gating is the practice of restricting access to sections of the gameworld until specific prerequisites are met," Gaynor defines. By delaying the player until they meet certain conditions, designers can keep control over the story’s pacing. These mechanics can be characterized in a few ways: Distributed vs local, systemic vs. special-case, or intuitive vs unintuitive.
For example, the mechanism in Legend of Zelda that locks all doors until a player defeats all the enemies inside to get a key is local and systemic – yet unintuitive, since there’s nothing in the real world that works that way . "Yet it works – encounter it one time, understand it every time you encounter it again."
In Resident Evil, the insignia door requires an insignia key – it’s distributed, as the door and the key are in separate locations; it’s special-case, since the key works only in that one situation, yet it’s intuitive, in that players can understand that a specific door may require a specific key to open.
Gaynor began working on the BioShock franchise with BioShock 2, in 2K Marin. In the first game, the player must reach Dandy Dental, but finds a wall of ice in the way. At the beginning of the game, the player has few tools available, none of which could resolve the ice blockage. Only later when the player finds the Incinerate plasmid in the crematorium are they able to clear the blockage – an example of a distributed, systemic and intuitive gate.
"Gating tools empower the player, because they obey consistent rules," says Gaynor. And they encourage players to explore and observe their environment, looking for opportunities to use the rules they’ve learned. "They allow the player to make micro-goals within the authored quest goals, and explore the world using tools that they’ve acquired."
Player tool gating isn’t limited to just passages and doors, though – in Super Metroid, one of the best examples of progression gating, observant, experimental players learn that the freeze weapon allows floating enemies to be used as platforms.
How Minerva's Den Uses Gating
When designing Minerva’s Den, the BioShock 2 DLC the design of which he led, Gaynor knew he wanted to build a self-contained experience that strips the player back to the bottom of the growth curve and allows them to rebuild. Since the player has no tools at the beginning, it was the perfect canvas for this style of storytelling.
Minerva’s Den as a place is Rapture’s technology center, with three separate areas that are connected by a central hub. In the center stands a recognizable landmark statue with directionality that allows players to orient themselves as they pass through.
At the outset, each area is locked: Two with panels that require electric jolts, one with a door control panel. After reaching the first objective, the player attains a hack tool – and at the same time the story provides new information that lets the player know their ultimate goal. The player intuitively knows to explore the area that’s accessible first – the door control that can be hacked with the tool – and from there, they gain the Electro Bolt plasmid that lets them open a different area to the next objective.
Simply through the placement of binary gates and gating player tools, the player’s path through the game world becomes complex, an ideal framework on which to build the storytelling. Key characters and plot elements can be introduced through the environmental storytelling the player sees, and the placement of the voice recording supports and complements the pacing of the path the player is following. When the designer can view the predictable map of the player’s journey, he or she can see how and when to lay clues or story elements in a way that best serves the pacing.
Four Rules Of Implementation
From this process he found four concrete takeaways: First, "the player’s top-level goal should always be known at the beginning of the tool chain," he says. "Their pursuit of this top-level goal drives them to seek out the intermediary tools they need to achieve it… it allows you to have fewer authored goals that are handed directly to the player, because they can find those intermediate goals themselves" by experimenting and exploring within the environment, which is more satisfying and rewarding for players.
Second, gates should be clear and intuitive – "anything that can short-circuit your tool gating should be regulated," Gaynor says, explaining how all other sources of fire besides the Incinerate plasmid had to be eliminated for BioShock’s ice gates to work.
Designers can allow players smaller ways to explore sequence-breaking if they want or if it gives them a greater sense of freedom, as in players being able to pick up Telekinesis in BioShock before they are instructed to get it. For the game to recognize that (instructing them to "use that thing you already have" versus to go and get it) can be very memorable and is a relatively small investment for the designer, Gaynor advises.
Third, level layout is key. The spoke-based map structure for Minerva’s Den was helpful to support these gating techniques, Gaynor says."If you want the playtime of a non-linear level to increase, you can use these kinds of strategies to pull the player through… and to re-use geometry," he recommends. "But to this end, the tool itself should be at the far end of a spoke… and have a strong central spine."
Further, tool gates should always gate off entire hubs, he advises. Players use minimaps to see which places they have yet to explore – when only small places are gated their relevance becomes unclear, whereas gates at the beginning of the spokes are a clearer way of communicating with the player about where they need to go. Even if players never use the map, major areas have very clear signage. "Placing the gates at the entries of the spokes creates natural emphasis," he says.
Following these principles regularly creates "a highly schematic level sketch that defines a reusable formula for creating these kinds of experiences", says Gaynor. Theoretically, the technique could be expanded to a limitless chain to maximize a single hub – the required tool chain forms a nested goal structure. But too many steps and overcomplexity and the players will forget their goals and become disinvested. A more sustainable expansion is a series of hubs, where each one has its own high-end objective and relevance to the story.
"It’s as close to a scientific formula as you can get when it comes to level structure," Gaynor says. "But it’s not any kind of silver bullet; it’s a solution to a specific set of problems."
One limitation falls out of the formulaic nature itself – if naturalism is important, then exclusively using this approach on a large scale can become very transparent and feel mechanical. In higher-fidelity games with fully-rendered worlds, story and characters, "moderation is key to success," he says, praising Batman: Arkham Asylum as an excellent example of diverse tools in use. There is progress gating, but players also have other choices and objectives, like rescuing hostages.
It also can create a limitation on the player's long-term choice, since restricting the pace at which a subset of abilities or upgrades are offers disallows the designer from giving them many options early. And it also limits the ways players can take ownership -- for example, everyone concludes Super Metroid with the same Samus.
"I find it interesting to have that variation between player builds," Gaynor says.
"Player tool gating is very powerful," he says. "Do you want to define a predictable path through a space that is not linear? Do you want to allow your player to define their own goals in opening new areas that you don't give them directly? If this is an approach you find interesting, it can put a lot of power into the player's hands to progress through the world using the world's rules."