Outer Wilds from Mobius Digital is a game whose universe makes you feel small – like a cog in a gargantuan wind-up clock. It's a universe that's ambivalent to your existence; one that shrugs at your presence and absence alike.

All that taken into account, Outer Wilds is a place that piques your curiosity, and constantly nudges you toward finding out the secrets of an ephemeral solar system.

Here's how this IGF Seumus McNally Grand Prize-winning game works: You're an astronaut from the planet Timber Hearth – the first one of your people. You wake up fireside, you jump into your spaceship, explore, then after 22 minutes a supernova destroys your solar system and you die (if some kind of horrific space hazard didn't kill you before that). You then wake up fireside again, with all the knowledge you acquired in your previous  playthroughs. You venture forth once again.

"It was really important that in the game you never got the sense that the world revolved around the player like it does in a lot of other story games, where clearly everything is built for [the player]," said Alex Beachum, designer on the game. He started working on Outer Wilds several years ago as his master's thesis, and it evolved into a commercial release published by Annapurna Interactive last month.

"Everything is on its own clock and things are changing and happening whether you're there or not," he said. Outer Wilds' planets operate on a physics-based system, which gives the solar system and its planets life and behavior of their own.

"[The time loop] helps it feel more like you're part of this world but it's not for you," said Beachum. "And it also works with the whole idea that the only thing you can bring back in time with you is your memories. So it really focuses on knowledge being the only real thing of value in this world, because what else can there be if you're going back in time, all the time?"

At the core of Outer Wilds' design is curiosity, and motivating the player to unravel the secrets of the solar system without heavy-handed prompts telling them to 'go here' and 'go there.' While the solar system is open-ended and players can visit whichever planets they choose, this isn't a space opera – Outer Wilds has a compact, concentrated solar system that favors depth over sprawl.

This means that one planet or satellite you may visit may give many clues for you to piece together to answer questions like, 'can this time loop be stopped?' or 'what happened to this ancient alien race?' Eons-old conversations are the breadcrumbs that you discover, which come together to tell you where the next mystery lies.

Getting players curious about the answers to these big questions was relatively easy, but designing for smaller moments of curiosity and discovery took perhaps thousands of hours of playtesting, said Outer Wilds fellow designer Loan Verneau.

"We learned really good design lessons from a lot of playtests of the game, things as obvious as like, if you want people to care about the text they're reading, it helps if the people they're reading about are going through the same things [as the player character], or are experiencing the same feelings," he said.

"If you can relate to the character you're reading about, then it stops being like, 'I found a book in Skyrim!' and more of a like 'I want to know what happened to [these extinct aliens] because I'm here too.'"

Designing for curiosity presented other unexpected difficulties during the game's development. The final version has the player being proactive in their exploration; they initially gather launch codes, then venture forth in their spaceship.

But an early version of the game tried piquing players' curiosity by initially having an object from space crash into your village like a meteor.

"Oh a thing falls from space, that'll get them curious, right?" said Beachum. "And it just super didn't work at all because players weren't familiar with the village yet. So they have no reason to be more curious from this new arrival. That [object from space] is not new to them to them [when] everything is new.

"I feel like one of the big lessons is that if you want to make people curious, you can't expect someone to be curious about something specific unless they're already familiar with everything in their immediate vicinity."

"We spent a lot of time [on this] as it becomes sort of a gatekeeping thing. Are [players] ready to learn? Will they care about this information?"

Curiosity is a catalyst that drives the pursuit of knowledge. Mechanically, the time loop in Outer Wilds is the vehicle for the accumulation of knowledge across many cycles of life and death. Thematically, Outer Wilds emphasizes the intrinsic satisfaction of discovery – something that's missing in a lot of games which are about making numbers go up.

"One of the original goals of the project was to make a game about space exploration, or even just exploration, and why we explore as humans," said Beachum. "The goal was to make a game where the only possible reason you could have to explore was for the sake of curiosity. 

"The way we ended up trying to do that was, 'ok, well if we remove any other reason you could possibly want to explore - collectibles or upgrades, explicit, tangible forms of progress - if you get rid of those, all that's left is you wanting to piece together what's going on. 

"That became the focus, and the time loop just worked well with that, because it plays into the whole 'knowledge is the only thing you get' idea."