Coding for Fun in the World of Replicube

Late last fall, I stumbled upon a post promoting a cute little puzzle game called Replicube by Walaber that took me on a short journey and made me fall in love with coding again.

Replicube is my favorite game I played in 2025—an elusive honor given how many games I play each year and how much talent in the indie game scene is producing wonderful and fascinating things every single day. Replicube was neither the most mechanically ambitious nor highly polished game I played last year. So what makes it so good?

The premise is digestible at a glance: using code, reproduce a voxel object however you see fit. I've always liked the novelty of games that teach you coding, but as someone with years of experience already, I wasn't sure I would get much out of playing one myself. Still, I could not help but be drawn in by its lovely presentation and had to give the demo a spin.

I was hooked instantly. The game drops you into a fictional IDE on a fictional OS, with fictional people sending you real puzzles to solve over a colorful desktop with relaxing music. I am someone who has always had a passing interest in shaders and graphics programming, and within the first hour of playing, it was quite clear that Replicube was made to nurture that curiosity.

The game starts you off with the very basics: three existing spatial values to work with (X, Y, and Z) and sixteen colors. Code you write is evaluated on each voxel and determines the output.

For example, the following code...

...will output a blue cube matching the dimensions of the output area. For readers less familiar with coding, this code is simply saying "be blue", which runs on every available voxel.

Likewise, if you apply simple conditions...

...the output quickly changes to match your new code.

From this simple foundation, it becomes frictionless to teach the players fundamental building blocks of coding: syntax, conditionals, comparators, boolean algebra, variables, etc., until the player has built up all the tools needed to tackle open-ended puzzles without guidance. Later puzzles explore more complex topics like recursion and fractals.

What is beautiful to me about Replicube is that it is meticulously designed as an open-ended learning environment. You are armed with basic concepts plus a bit of documentation containing common mathematical functions and quick references, then you are let loose to sink your teeth into each puzzle and discover your own solutions. Curiosity and experimentation are rewarded, and everything you learn is cumulative. There is a sticky note feature that allows you to leave yellow notes on your in-game desktop; I used it to keep a reference of equations for various simple and complex shapes that I'd want to reuse.

The nature of the game also smooths out some of the rougher edges common to learning basic coding. As soon as you stop typing, your changes are reflected in the output window—immediate visual feedback for you to evaluate as you continue to iterate. Furthermore, because the code you write is strictly raw math and logic, the player need not waste time on bug-fixing and other arcane problems that come with the territory of real-world coding. Problems will only ever be with logic and implementation.

Solutions can become quite complex in the later puzzles!

In addition to the puzzles, Replicube also has a free edit mode where you can make your own objects freely as well as a 2D mode where you can draw lovely little pictures. Anything you make can be published on CubeNET, an in-game forum and browser where you can chat with other players, play and upload more 3D puzzles, or marvel at other players' 2D creations. The forum is very reminiscent of internet communities from the early 2000s, though in my experience the people on CubeNET are much more easygoing and friendly.

For the uninitiated, this still might sound nerdy and maybe not fun on paper, but making colorful objects and solving puzzles with code as they are presented in Replicube is something I think anyone can enjoy. It always does feel corny to tell people that learning can be fun, but games as a medium occupy a unique position in that they allow players to learn by doing, and I staunchly believe that doing is both the most engaging and most effective way to learn. The satisfaction of writing code that produces a colorful lil' sushi roll, a guitar, or a school desk reminds me of why my younger self took interest in coding in the first place. It is a set of tools, and coding can be as useful, artistic, or expressive as the wielder wills it to be.

So, go and give Replicube a try! We live in a world that so often sees and uses code as a means to an end. Be expressive instead and find a little joy in coding for its own sake. I sure did!