Fallout co-creator Tim Cain says trying to cram everything into a game is the most common design mistake

Fallout co-creator and veteran RPG designer Tim Cain has a new YouTube video out about the game design pitfalls that regularly derail development projects. The central theme is what he calls a "design pothole" – a problem easy enough to dodge if you know to look for it, but one that can "wreck your transmission or blow out a tire" if you're charging ahead without paying attention.

Cain, who recently returned from "semi-retirement" to resume full-time work at Obsidian, pointed to one of the most underrated skills in game development: knowing when to stop.

"As a very wise designer once told me, 'A game that includes everything is about nothing.'"

Overambition, he argues, tempts designers across every discipline. On the narrative side, a game's lore can slowly bloat to include aliens, psionics, magic systems, and murder mysteries until the whole thing loses its identity and any sense of direction.

"The same thing can happen with mechanics," Cain said, where "you start adding mechanics not because they belong in there, but because someone has told you, 'Well, you got to have crafting, you got to have item degradation, you got to have base building. It's what everybody wants these days.'"

That kind of feature creep, according to Cain, ultimately destroys a game's focus and clarity of purpose. Everything added should serve a concrete goal – and "I think it's neat" doesn't qualify.

The past decade of gaming offers plenty of examples to back that up. Series like Assassin's Creed and God of War have at various points been weighed down by crafting systems and Destiny-style loot – elements that, at best, existed on the periphery of the experience rather than reinforcing it.

Cain says the same absence of focus produces other kinds of missteps too. Over his career, he's encountered design documents where writers described locking the player in a room until they performed a specific action, or flatly declared they would "make" the player feel a certain way – rather than describing how to actually evoke that feeling.

Both approaches reveal a fundamental misunderstanding of why someone picks up a game in the first place. And the root cause, Cain argues, is a lack of clear design pillars – the guiding principles that keep development anchored to its original vision.

"If at this point you don't know what all of this is in service of, you're going to run into problems," Cain said. "You should know why. Why am I doing all this? Why did I make this setting and tell this story with these mechanics?"

This isn't the first time Cain has pushed back on scope creep. Last November, he urged developers to learn from 1980s games, which were forced by hardware limitations to keep their ambitions in check – and were, in his view, better for it.

Now that hardware is essentially limitless and productions have ballooned in scale, developers often end up with more rope than is good for them. Design pillars, Cain insists, are what keep that abundance from becoming fatal.