We speak to Stefan Heinz, the lead developer on Portal: Revolution, a new fan-made campaign prequel to Portal 2.

Portal: Revolution is a new, free fan game, based on Valve’s Portal series — it’s available on Steam now, having launched, on January 6, 2024. 

The game, technically a mod for Portal 2, offers up a new, roughly eight-hour first-person puzzle-platform experience — all of which is set before the events of the second, award-winning puzzler from Valve. During the eight-hour campaign, players will tackle around 40 new, increasingly puzzling test-chambers. 

The ambitious free game is the culmination of a years-long effort, all led by Austrian game developer, and recently graduated, Stefan Heinz. We spoke with him ahead of the game’s release to find out a little more about this neat project. 

Stefan Heinz — Second Face Software
Stefan Heinz

Stefan’s love for Portal is a long-running one — he shares with us that it was seeing his dad play the original game (released back in 2007) on the family PC that sparked his prolonged interest in the series. Stefan notes that seeing the puzzle platformer in action for the very first time “immediately blew my mind”.

From this point — despite, as a then nine-year-old, being a little scared of the in-game turrets — Stefan started playing the game themselves and he has been hooked ever since. 

For those unfamiliar, Portal’s core gameplay centres around solving puzzles in 3D environments called ‘test-chambers’. In these chambers the player must experiment with switches, boxes, and other devices, moving both them and the main character via portals — these titular portals are created by using the ‘Aperture Science Handheld Portal Device’, aka the portal gun. It’s a superb, innovative and smart puzzler with a unique, fun concept at its heart — it’s aged incredibly well and remains a must-play. 

A love for the Portal games, along with his keen, growing curiosity for both computers and programming (another thing he picked up from his father), resulted in a 12-year-old Stefan messing around with the mapping tools found in Portal 2. From here, Stefan’s delight for both gaming and coding developed further, and he soon found himself tinkering with the likes of Java, Android apps, Minecraft mods, and more. 

Such an interest in programming led Stefan to study software development at college, but as this “can be really dry and dull”, he also took game development classes, along with exploring modding in his free time — it’s here where the Portal: Revolution project was essentially born. 

"I still consider myself mainly self taught in game development however. The classes covered some theory, which I found really interesting, but we mostly made small 2D games in Unity or made animations in Blender, which I don't think taught me much new at that point."
Stefan's desk, complete with Aperture Laboratories custom mechanical keyboard

With a thirst for game development, along with seeing just what was possible in the mod space (such as with 2015s Portal Stories: Mel), work on Portal: Revolution was underway. Stefan notes that the project started, in some form, so far back as 2016, but “has evolved drastically over time”. 

The current iteration of the game that we can see on Steam today started its life just ahead of the pandemic in 2019, and really took shape in 2020 once Stefan and his now small team got hold of the source code for Portal 2 from Valve. To put a date on it, this project has been a consideration since 2016: 

“I still like to say that the mod started in 2016 though. The rough story outline has never changed since then and I learned a lot from those early iterations.”

Eight years on from that initial mod idea, the game is now a playable reality — a working collection of all of Stefan's ideas. But, Stefan is keen to point out its existence today is thanks to a real team effort that came together during the development process. 

The team behind Portal: Revolution ebbed and flowed somewhat over the years, but landed on a core of seven people, which includes the likes of voice actors, music producers, 3D modellers, and programmers.

Stefan speaks with a certain joy about the creative process fostered during development:

“I think the thing that makes me the happiest is just how incredibly dedicated and creative our team is. The collaborative atmosphere of everyone working together to create something great is unmatched.”

He adds that the team had no prior game development experience ahead of working on Portal: Revolution, instead learning what was “needed along the way”, with some team members finding new passions during the development journey. 

“Tristan originally joined the team as an environment artist, [..] Now he is our lead 3D modeler and has created most of our original 3D assets. The portal guns and player model are just two of his spectacular assets. I don't know anybody who can use Source Engine's rather primitive shaders to create materials as good as his.”
“Rory originally joined as a 3D modeler, but later went more and more into graphics programming. He managed to implement real-time volumetric lighting into our game engine after years of hard engine work.”

Portal: Revolution is available on Steam now — this labour of love is free to download and play, but you will need to have Portal 2 in your Steam library. Stefan tells us he's been testing the game on his Steam Deck too, ensuring that the native Linux build runs just right — music to our ears.

As for what's next? Well, Stefan shares that after fixing some bugs, there's still some post-release content planned for Portal: Revolution, including an in-game developer commentary, a soundtrack release, and even authoring tools for mappers. Once that's all wrapped, Stefan points out that he'll have been working on Portal fan content such as this for almost half of his life.

Beyond that, Stefan has no further plans to make another mod such as this, but has some early ideas for a potential first-person shooter project someday. In the mean time, it's over to Portal fans to explore and enjoy this true love letter to one of gamings most revered puzzle classics.

Portal: Revolution on Steam
The Portal Mod you’ve been waiting for. Delve into a new story with original characters, spanning over 8 hours of gameplay and featuring over 40 new challenging test chambers which make use of new mechanics.
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