The iOS principle: Croteam on porting its puzzle hit to iPhone

Lead Programmer Karlo Jež on how the Metal API enabled the team to squeeze the game onto iOS

The iOS principle: Croteam on porting its puzzle hit to iPhone

A good time before Croteam's acclaimed and thoughtful first-person puzzler The Talos Principle had launched on PC in 2014, the team were mulling over the potential of taking the game to mobile.

At the time, industry observers may have considered the Croatian outfit rather over-ambitious in wanting to take the polished 3D release to smartphone. After all, it is so perfectly suited to play on a home computer, and those few years ago mobile was still incomparable to console.

What's more, we all know that the first rule of mobile success reads 'design for the platform'. The early days of smartphones taught us that.

Design over platform

Trying to squeeze gaming experiences primarily designed for gamepads, mice and keyboards onto smartphones so often requires something much more significant than a straight port.

Still, very early on Croteam couldn't help but ponder how they could harness the popularity of mobile. And it turns out they were always designing a game to transcend any particular platform's physical conventions.

It might just be that is the real secret to triumph across PC, console and mobile with a single property.

"Going with the game design over platform always works," muses Karlo Jež, Croteam's Lead Programmer on The Talos Principle for iOS, which launched earlier this month.

"You don't really want to be held back by limitations of any kind, and you don't ever want to make compromises. Luckily, due to Talos's relaxing nature it was always a good fit for mobile.

"We had some great control options in mind already, so the biggest limiting factor was the hardware itself. Now, with more powerful devices and Apple's Metal API, bringing the game to mobile was a relatively easy task."

The appeal of mobile more broadly was somewhat more clean-cut for the team. The Talos Principle, Croteam will tell you, is something the team cares about deeply, and that they are rightly proud of.

Going with the game design over platform always works.
Karlo Jež

The studio takes no shame in admitting they want their game to reach as many players as possible and mobile provides an obvious vehicle for that ambition.

To the Metal

The aforementioned Metal API provided Croteam with everything they needed to move on iOS. An Android version of The Talos Principle had already seen release in 2015 – some months before the PlayStation 4 port of the game – but that didn't stop Jež and his colleagues longing to embrace the iPhone.

"Making the iOS version of the game wasn't as time consuming as we originally thought, and most of that was due to the Metal API being easy to work with, well documented and supported by the Apple team," he explains.

"It didn't hurt that it wasn't much different from the Vulkan API that our engine already supported. As far as the advantages go, Metal allowed us to properly use the full power of all supported devices so that the game can look the way it does."

The Talos Principle certainly sings on iOS. It has always been a mechanically rewarding, almost tactile game; playing it can be immensely satisfying, and the visual – and aural – polish is a significant part of that experience.

Croteam, it seems, had always been ready for iOS; the team just felt the need to wait for the platform and its ecosystem of development technology to be ready for the game.

Of course, coming to iOS – even with the Android version long ago released – was not without its challenges.

Balancing act

"Adjusting the interface to many different sizes and resolutions [was a significant challenge]," reveals Jež, who is not just talking about the pure functions of UI, but equally Croteam's carefully curated UX.

"It had to look and feel right across a range of devices, including smaller iPhones and large iPads. Many elements needed to be scaled individually so that we can figure out what works best. It was a gruelling process, but I believe we found the right balance, and I hope it shows."

It was a gruelling process, but I believe we found the right balance.
Karlo Jež

By the reaction of the game critics and existing fans of The Talos Principle, it appears that laborious task was worth the effort. The reviews have offered high praise indeed, and near consistently.

If Croteam has learned one thing from the iOS porting experience, it is that the classic rules still apply.

"Think about playing your game on a smaller screen using touch controls, and if you think you'd be having fun – go for it. It's as simple as that," Jež concludes.

A pragmatic insight indeed, but a tip still not heeded by many game studios today – or perhaps publishers hungry for ever more audience and the heady allures of smartphone monetisation; maybe because to make a game thrive on mobile like The Talos Principle, it needs to be as good as The Talos Principle in the first place, regardless of platform at all.

At least, that logic has worked for Croteam.

Will Freeman is the former editor of trade publication Develop, having also written for the likes of The Guardian and The Observer.