How a seemingly small change can spiral out of control.

How and why games are built from such fragile webs

The ‘domino effect’ is a term introduced to me by Bill Gardner, lead designer of BioShock and BioShock Infinite, to describe an intriguing aspect of game development. It’s a term for the pitfalls of the iterative nature of game making, and the fact that the further along you are in development, the more likely it is that changing even a small aspect of a game can break massive sections of the entire project. David Pittman, cofounder of Minor Key Games and creator of indie immersive sims Eldritch and Neon Struct, explains: “A mechanic in isolation may look simple, but the intersection of mechanics creates a complex system of dependencies. That’s usually a good thing for systemic games; it provides the player with a coherent simulation that enables them to plan, act, and react. But complex systems can also be the source of many bugs and delays, as the combinatorial interactions of systems are difficult to predict.”

The Deep End Games found this to be true on a narrative as well as systemic level in its attempts to remaster its horror adventure, Perception. “We had a few domino effect moments, but our remaster patch that included major changes to Chapter 2: The Ticket, had to be the most drastic,” says writer, producer, and cofounder Amanda Gardner. “This chapter follows the story of a war bride named Betty, who wants to serve in the war beside her husband to keep him from harm. Betty’s brave attitude was overshadowed, we found, by confusion among fans as to what actually happened to her at the end of the level.” This prompted a series of changes that resulted in an overhaul of the chapter, including the removal of a sideplot focused on a lucky gun that they had unintentionally emphasized to the detriment of the story.

“When we decided to remaster Perception, we did an amount of story streamlining, but removing references to the gun shifted a lot of pieces. For example, the first use of ‘Friendly Eyes’, the app where Cassie can get descriptive assistance from a person with sight, had to be moved. But because it was an introduction to the app, we had to ‘teach’ people how to use it at a different point, which made us have to move around other audio touchstones.

“We also realized how removing the gun would be a great way to reframe Betty and underline the feminist themes,” Amanda says. “When Betty is presented in the original, she is feeding breakfast to a hallucination of her husband’s dead body. We realized this made Betty seem unstable. By removing references to the gun and presenting the opening scene in a different light, we were able to present Betty as a level-headed woman in a precarious situation, rather than a grief-mad widow.”

Such ripple effects become more likely the further you get into development, especially as certain assumptions are set in place. “To change one of those assumptions later in production requires tearing down the entire building,” Pittman tells me, “at a great cost and loss of productivity.”

“What should’ve been a simple fix took hours and hours of back and forth”

Jumping through hoops

Even something like jumping can be a huge commitment. “The gist is that once you choose to add jumping to a 3D game, every asset needs a collision mesh, and anywhere you don’t want the player to be able to get to needs collision planes placed to block it off,” says Fallout: New Vegas writer and designer Eric Fenstermaker. “Any errors in the placement can result in the player getting stuck.”

Due to engine limitations, the physics calculations for New Vegas only occurred in a new frame. This let the player get stuck in the environment if the framerate plummeted. The problem was exacerbated if players didn’t have adequate hardware. “I remember a section at the end of the monorail at Camp McCarran that we didn’t want the player to be able to get beyond,” Fenstermaker recalls, “but no matter how I placed collision planes, QA would always find a way to get through it. What should’ve been a simple fix took hours of back and forth.”

David Pittman also explains why features, visuals or plotlines can remain in a game’s code after being cut. “A feature that seems important during preproduction may be vestigial by the time a game ships. When that happens, it may be easier to leave the vestigial feature in than to cut it out, especially if it’s a ‘load-bearing’ feature that could cause a domino effect by its removal.

If you’ve ever wondered why a developer won’t make a seemingly simple change, or pieces of what a game used to be still lurk in a title’s code, now you know. By Xalavier Nelson Jr