Nobody can agree what an ‘immersive sim’ is, but OG Fallout lead Tim Cain has his own definition: ‘The very elements that make something an immsim are the ones that I also think make good RPGs’
Immersive simulation games—immersive sims for short and “immsims” if you’re a true freak—are a lot like sandwiches, soups, or pornography in that it’s easier to give an example than a watertight definition. Dishonored, for instance, is definitely an immsim; it simulates a lot of factors that respond to the player, boasts open-ended levels, and encourages all sorts of emergent shenanigans.
But those same things are broadly true of Far Cry Primal, a game that probably isn’t an immsim, or at least not acknowledged as one by immsim fans. How can that be? Well, Fallout co-creator Tim Cain took to his YouTube channel Monday to try and get down to brass tacks.
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It might seem like an odd subject for Cain to tackle, given that, as he notes in the video, “so many of my hundreds and hundreds … of videos are me talking about roleplaying games because that’s pretty much all I’ve made since 1993.”
He has even tried to define “RPG” in the past, which seems even harder than defining immsim because there are a hell of a lot more of them. But Cain said he sees a lot of overlap between the two genres’ design goals and wants to hone in on a definition for both anyway.
His definition boils down to three core elements. The first is that the game contains “many basic rules on how the world works.” The second is that “those rules interact with each other to create a large number of emergent systems.”
Cain quickly defines emergent systems as “features that were not necessarily intended by the original designer, but result from the application of those basic rules.” He also shouts out Maxis’s Will Wright (The Sims, SimCity) as the “master” of these two rules.
Cain’s third rule is that “the player, as well as everything else in the world” must adhere to all the basic rules from his first point. Like any genre, it’s an ad hoc spectrum; the more your game embodies those qualities, the immsimmier your game is.
He goes into more detail in the video, but those three points make up his thesis. I’m no expert on the genre, but it seems like a workable definition to me, though it probably includes some games that don’t belong there.
One game that came to mind for me was The Legend of Zelda: Tears of the Kingdom; it follows all of Cain’s rules due to its engineering sandbox, but I think it’d be controversial to call it an immsim.
Of course, this hasn’t stopped the thought leaders of PC Gamer: All the way back in 2017, senior editor Wes Fenlon argued that Breath of the Wild was the most PC Nintendo game ever largely on the grounds of its immersive simmitude.
All these genre tags are easy to fight over, but they’re useful even with the vagueness involved: as shorthand, and as a starting point for discussion. They’re why I can tell you that if you care deeply about this topic and love games like System Shock or Dishonored, you’d probably love Skin Deep, PC Gamer’s best immersive sim of 2025.
