Toby Fox, the creator behind the critically acclaimed Undertale and its spin-off Deltarune, has opened up about his distinctive and often inefficient game development methods. In an interview, Fox described his approach as "stupid" in its laboriousness, yet acknowledged that the results have pleased many players. This unique process is evident in Deltarune's RPG gameplay, which consistently introduces novel mechanics and challenges.
Fox explained that a more conventional development strategy would involve reusing game mechanics, such as similar enemy attack patterns or stat blocks, which can be easily tweaked in a database. However, in Deltarune, each element is designed to be unique. "Everything in the game is simply a container for a never-before-seen gimmick," Fox stated. This means every enemy features new bullet patterns and actions, and each area presents original puzzles. While this approach contrasts with traditional RPGs, which Fox cites as some of his favorites, it significantly increases development time.
This dedication to originality results in gameplay that actively surprises players. Battles can incorporate unexpected elements like rhythm game segments or roulette machines as damage mechanics. Fox believes this iterative creation of unique encounters is not only more enjoyable for both players and developers but also allows for more creative approaches to difficulty. Instead of relying on players' mastery of existing systems, like bullet hell dodging, new gimmicks can introduce fresh challenges that don't require prior genre expertise.
The Long Road to Deltarune
The development of Deltarune has been a lengthy process, with its first chapter released as a demo in fall 2018 and Chapter Two following in fall 2021. Chapters Three and Four arrived in June 2025, with a total of seven chapters planned. Fox has kept fans informed through detailed developer blogs, outlining the minutiae of game creation, including map design and the implementation of new gimmicks.
Development has faced several hurdles, including localization, console porting, debugging, and adopting a new game engine. To address these challenges and accelerate progress, Fox expanded the development team, hiring a producer with the explicit goal of finishing the game. He acknowledged that the sheer volume of work and his own physical limitations, such as wrist issues that require him to use voice-to-text for communication, make a solo development effort impossible. Working with a larger team also brings the benefit of collaborative idea generation.
However, managing a larger team has introduced new complexities for Fox, who maintains a strong directorial role. While Undertale provided a foundation, it did not fully prepare him for team coordination. Fox described his directorial role using a kitchen analogy: he is in charge of the overall vision, while others prepare the soup (game elements). His primary concern is ensuring everything is fun and aligns with his narrative intentions. He noted that distinguishing between a bad recipe of his own making and a flawed execution by a team member is more challenging when not directly involved in all aspects of programming.