How do you go about testing a game like Blue Prince? Dogubomb's puzzle adventure is one of the breakout hits of 2025, captivating – and confounding! – players with its mesmerizing roguelike gameplay and atmospheric (and literal) worldbuilding.
We interviewed Dogubomb’s Tonda Ros to learn about the journey to make Blue Prince, including prototyping, playtesting, and maintaining motivation to finish over eight years of development.
You came into the games industry from a prior background in film. How have your past professional experiences influenced how you think about game development?
I spent over a decade working in the film industry as a cinematographer, which I think informed the way I approach lighting the rooms of the game. It helps that placing lights in a 3D space is a surprisingly similar process, only in Unity you have the added benefit of being able to use Culling Masks to isolate objects on specific layers, which is an incredibly helpful feature that I wish I could magically bring over to filmmaking! I think there’s a lot of overlap between the two mediums.
Where did you learn to code?
I think all of the coding languages I’ve ever dabbled in have been more or less self taught with wildly different ranges of proficiency. My very first experience with scripting was in the game engine ZZT in the ’90s. From there, I transitioned to Qbasic, and then to Basic83 which I taught myself in high school when calculator games were all the rage. Unfortunately, that’s where the game making journey of my youth ended, as I soon shifted to web languages. It would be another two decades before I got back into development.
How did you land on Unity to make this project?
I had made a post in a game development forum inquiring about development tools and engines. I was looking for advice for how to get started and I was looking for something that was easy to pick up with a low barrier of entry. Several people suggested I look into Unity. Within a day of downloading the software, I was absolutely hooked and never looked back.
Blue Prince’s game loop is very meditative, with visuals and music both playing major roles in drawing players into the flow of the game. What was it like trying to “find the fun” in early iterations, before you had these elements in place? How did you know you were onto something during prototyping?
After speaking with other devs, I don’t really think I appreciate how lucky I got in the prototyping stage. That initial idea of “opening a door and selecting one of three different rooms” just felt perfect from day one, I think it was only one week into development before I got to personally open my first door. That moment of seeing the room I had selected magically appear was the moment I knew I had stumbled onto something special. The core design of the game never changed from that first week.
You’ve said in interviews that you prototyped this game using Unity Asset Store tools before completely overhauling the graphics later. Which Asset Store tools did you find most useful for making Blue Prince?
The Asset Store was critically important for allowing us to build up a prototype quickly. It is the reason I was able to create a full build of the game in 2016 without any prior knowledge of 3D modelling. In that first week, I can remember creating my first rooms by scaling Cube GameObjects to form the walls, doorways, and floor of each chamber. I then turned each room into a Prefab, and used the Asset Store to search for furniture models to decorate each of these spaces.
Within a week, I had over twenty room Prefabs created and I used an Item Pooling system (also found on the Asset Store) to form the system that would instantiate each of these prefabs after opening a door in the house. Believe it or not, those Prefabs I created in the first week of development are the exact same Prefab assets we are using for our rooms in the final build of the game! Like I said, the core design has remained unchanged.
How did you approach user testing and game balancing for a project like this?
I knew it was going to be quite difficult to test Blue Prince given the extreme level of variation in each playthrough. The endless configurations of the game’s rooms can create so many unique situations that approaching the game with traditional QA is almost impossible. This led me to begin recruiting playtesters as early as 2020, a full four years before our release.
Over that lengthy testing period, I ended up watching over 2,000 hours of recorded footage. All of the insights I gathered from this process were derived from watching those sessions. Part of my approach is to simply observe and make revisions based solely on how closely player experience aligns with my own vision. This allows playtesters to approach the games as they would any other game.
What was it like integrating the feedback from these sessions?
Because of my method of reviewing playtester sessions' recordings rather than relying on surveys or direct feedback, my approach to utilizing insights to edit content happened more naturally as the game was being built. That’s part of the reason why I started playtesting so early to allow this process to run in parallel to development. If I felt something was lacking while watching a playthrough, like a cool item to synergize with a player’s unique strategy, I simply added it to the game. Many of the rooms and items in the game were formed gradually in this manner, the way footpaths are forged by wearing down the grass, step by step, through repeated travel.
I didn’t set out with a blueprint for how each element of the game would be shaped. Instead, I watched where players naturally wandered, where they paused, where they struggled. And in response, I shaped the game around those stories, letting the terrain of playtesting slowly erode the unnecessary and reveal the paths underneath.
What was it like working on Blue Prince solo and then adding more people onto the team? Was it difficult to relinquish control over the game?
The question isn’t what it was like for me working with other folks on the team, but what it was like for them! As an artist I can’t imagine it was very fun. After working for so many years alone and after growing so personally attached to the house, I found myself completely unable to relinquish control even to the most insanely talented members of my team. I know how difficult that can be working with someone like that, so I am even more grateful to everyone who put up with my demanding demeanor and nitpicks. Maybe next time I’ll learn to let go a little more.
In particular, I’d like to single out my art director Davide Pellino, who worked beside me for several years to develop the look of the game. We bumped heads a few times, but collaborating together was an amazing experience, and I think it says a lot that we are both equally overjoyed and proud of the game’s final visuals.
Blue Prince has been in development for eight years. Any particular high or low points? How did you stay motivated and keep going?
There were a few points where I almost abandoned the game in favor of a new project. I’m sure many developers can relate to the tempting allure of a shiny new idea. Thankfully, our producer, Axel Haavikko, ensured that Blue Prince remained at the forefront of Dogubomb’s schedule, even if he had to sometimes ruthlessly prune other blossoming ideas in the flower bed before they were able to take root. If it wasn’t for him, Blue Prince would not have been completed.
When you started development, what did you think were the odds of success?
For me, success can be measured in two parts. First, how much enjoyment did I derive from the process? Every artistic medium is going to have its own quirks, tediums, and disadvantages, but if you are going to spend years of your life on a project, I think it’s really important that you create a workflow that you genuinely love and one that allows you to find actual delight in the day to day grind. It’s not an easy task, but if you can pull that off, then you have met my first metric of success.
My second measurement is an assessment of how pleased I am as an artist with the final product. How much was compromised? How close did I come to realizing my vision and my aspirations?
It wasn’t very clear when I first began what my odds would be of succeeding in either of these metrics. I wasn’t quite sure how much I would have to struggle with the technology, I wasn’t sure how long it would take to learn the ropes, and I wasn’t sure how much fun it would actually be.
It only took a few months of tinkering in Unity to have my answer. An answer punctuated in bold letters and clear enough that I decided to forsake my career to dedicate myself entirely to this project full time. The deeper I got into the project, the clearer it was that developing Blue Prince was quickly becoming the greatest of joys of my life. Discovering that was its own testament of my success in this venture.
How did you pitch Blue Prince to publishers? And what did they like about your pitch?
Blue Prince was funded entirely from ad revenue from a website I created about the game Magic: The Gathering. I was extremely fortunate, in this regard, as this enabled me to work on the game for eight years without the need to find additional funding. This also meant when I felt it was time to pitch Blue Prince to publishers, it wasn’t so much a pitch, as it was sending them a key to play the polished near-final build of the game.
This isn’t a very typical strategy, but it’s one that works for me, as I really do enjoy working on the game in isolation. I’m also the type of person who struggles to show people work in progress. Even for the other people on the team who contributed to the game, I wouldn’t even let them play a slice! They too had to wait for the game to be fully playable and near-complete!
You’re a major puzzle aficionado. What puzzle games have had the biggest influence on Blue Prince?
When it comes to my own taste as a player, I am really drawn to games where puzzles are integrated practically into the world. Where you're not so much solving a series of isolated standalone puzzles as you are uncovering the logic behind how the world itself works. For me, Riven remains the gold standard of this kind of design. Everything in that game makes practical sense, and you are able to solve things by simply making observations and logical assumptions about the world.
While I strive for that diegetic benchmark in my own design, Blue Prince also contains a huge variety of puzzle styles in addition to the environmental ones. I’m a huge fan of the logical problems devised by Raymond Smullyan and the word puzzles of Christopher Manson, whose book The Practical Alchemist is my favorite puzzle of all time.
If it’s possible to answer this without spoilers, what’s a small detail in Blue Prince that you’re fond of that players probably won’t pick up on?
I’m incredibly proud of our shader and accompanying unwrapping process. 99% of all of the objects in Blue Prince are using the same material and the same texture. What appears to be a hand-painted style is actually created by mapping each model’s UV maps to several texture atlases (one for each UV map). It’s a convoluted process, but I love it, and I think the individuality of the workflow lends itself to the unique aesthetics of the game.
Last question: Who is feeding that poor little hamster in the Bunk Room?!
I think there’s an assumption that the house manager, Anne Babbage, is making sure that the lil guy’s food bowl and water are full each morning that the Bunk Room is drafted. This is just me hypothesizing though, I’d hate anyone to take what I say as canon. The author is dead.
Blue Prince is out now on PC, PlayStation®5, and Xbox Series X|S. Explore more Made With Unity games on our Steam Curator page and get more insights from developers on Unity’s Resources page.
