⛰️ Kaizo Ascent: Celeste and Difficult Level Design as Community Practice. (forthcoming)

Abstract: Following its initial release, the developers of Celeste (Maddy Makes Games, 2018) opted to release a series of free post-game updates that gave players the option of playing a long series of extremely challenging levels that exponentially increased the difficulty of the base game. Due to the drastic increase in precision platforming skill that these optional levels require to complete, it can easily be argued that they are mostly intended for speedrunners and players who are otherwise fans of “Kazio” ROM hacks, a genre of custom levels first initiated by amateur modders and famed for intentional and often absurd degree of difficulty. Although the term can be loosely applied to any kind of intensely tricky platformer level design, it is most concretely tied to fan mods of the iconic SNES game Super Mario World (Nintendo, 1990). Taking a broader perspective and looking at the ongoing development practice of Maddy Thorson, Celeste’s creative director, writer, and co-programmer, the connection to Super Mario World and Kaizo level design becomes even more explicit as she has authored a number of these ROM hacks herself. Further complicating this interwoven diagram of influence between the histories of Kaizo community practice and Celeste’s development, the latter now has an open-source tool called the Everest Mod Loader that transforms Celeste into the same kind of highly mutable game object that Super Mario World has turned into, with a similarly ever-growing number of wildly difficult custom fan levels being continually released, speedrun, streamed, and discussed on community forums. Finally, to aid in these kinds of community efforts, Maddy Makes Games has also produced and released the source code for several “demakes” (Swalwell, 2021) of Celeste, encouraging fans to create their own unique variations using grassroots tools such as PICO-8.

This chapter will closely examine how Maddy Makes Games and the Kaizo ROM hacking community influence each other and, in turn, collectively influence the ongoing state of the precision platformer genre. Exploring these connections will reveal productive insights into how community-driven fan practices such as Kazio level design, ROM hacking, and open-source game development can work to influence the commercial game industry’s approach to post-release engagement and development. Building on relevant literature from game studies and fan studies, such as Brendan Keogh’s (2023) work on in/formal modes of game development and Boluk and LeMieux’s (2017) conceptualization of modding, this research will argue that by examining specific design choices and developer-community relationships, we can gain a deeper understanding of how game developers cater to niche communities and how those communities, in turn, shape games.

Keywords: Celeste, Kaizo ROM hacking, precision platformers, modding and open-source development, fan communities and game design, post-release game development

Recommended citation: Bailey, A. (2026). “Kaizo Ascent: Celeste and Difficult Level Design as Community Practice.” In The Effects of Community on Game Play and Design. Edited by Kevin Veale and Adam Jerrett.