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How New Retro Games Get Made: GB Studio, NESmaker and SGDK

2026-08-31 · Explainer

Once you have seen a few new Game Boy cartridges, a question starts nagging.

Who is still doing this? Writing assembly for a processor from 1989, on hardware with 8 kilobytes of RAM, decades after the last official development kit was thrown away?

The short answer is almost nobody, and that is exactly why the scene exploded. The people making new retro games are mostly not writing assembly. A set of free modern tools appeared over the last decade that let ordinary developers, and quite a few non programmers, build real games that run on real hardware.

Understanding those tools explains why homebrew stopped being rare.

The Old Situation

For a long time, making a game for a retro console meant one of two things.

You wrote assembly language, by hand, for a processor with severe constraints, managing memory yourself, with no debugger worth the name and documentation assembled by hobbyists reverse engineering the hardware. Or you did not make a game.

That filtered the scene down to a small number of extremely dedicated people. The results were often technically impressive and rarely finished.

What changed was not the hardware. It was the tooling.

GB Studio: The One That Broke It Open

GB Studio is the single biggest reason new Game Boy games exist in the volume they do.

It is a free, open source, visual game creation tool that exports real Game Boy ROMs which run on real Game Boy hardware. Not a fantasy console, not an emulator target. Actual cartridge ready output.

What makes it significant is who it lets in. You build scenes visually, place sprites, define behaviour with a drag and drop event system, and draw your art in a built in editor with the correct palette constraints already applied. You can produce a working Game Boy game without writing a line of code, and you can drop into scripting when you outgrow the visual tools.

The consequences show up directly in the shops. Deadeus, the horror game with 11 endings that gets recommended constantly and has had multiple cartridge printings, was made in GB Studio. So were a substantial share of the titles in Incube8's catalogue.

The constraints are real and they are part of the appeal. Four shades on the original Game Boy. Limited sprites per scanline. A small memory budget. Those limits mean a solo developer can finish something, which is the thing that almost never happens on modern platforms.

NESmaker And The NES Toolchain

The NES has a similar story arriving from a different direction.

NESmaker is a paid toolkit built around the same idea, letting people create NES games through a visual interface with modules for common genres, exporting real NES ROMs. It has been responsible for a wave of NES releases from developers who would never have written 6502 assembly.

cc65 sits at the other end, a C compiler targeting 6502 systems including the NES. It requires real programming, but writing C rather than assembly is a dramatically lower barrier, and the more technically ambitious NES homebrew tends to come from here.

The NESdev community is the quiet foundation under all of it. Decades of accumulated documentation, worked examples and hardware analysis, freely available. Micro Mages, which fits a four player co op platformer into 40 kilobytes, came out of developers with deep knowledge of that body of work.

Our new NES games guide covers what has come out of this.

SGDK And Why Genesis Homebrew Is So Good

We argue in our Genesis guide that the Mega Drive has the strongest 16 bit homebrew scene. SGDK is most of the reason.

The Sega Genesis Development Kit is a free, actively maintained, C based toolchain for the Mega Drive. It handles the tedious parts, provides libraries for sprites, sound and input, and lets developers work in a language they already know.

Combined with the Motorola 68000, which is genuinely pleasant to program compared to the 8 bit processors in its contemporaries, the result is a platform where a competent modern developer can be productive quickly. That is why Genesis homebrew includes things like Demons of Asteborg, an action RPG at a scale that would be implausible in hand written assembly.

The lesson generalises. Where good free tooling exists, a scene appears. Where it does not, the scene stays small. That is the entire explanation for why SNES homebrew is thinner than NES and Genesis homebrew, despite the SNES being the more beloved console.

The Rest Of The Toolbox

PICO-8 is a fantasy console rather than real hardware, meaning it emulates constraints that never physically existed. It has an enormous community and is the easiest possible entry point into constrained game design. Our PICO-8 guide covers playing and making.

TIC-80 is a free open source fantasy console in a similar spirit.

Various GBA and Dreamcast SDKs exist for the more powerful systems, generally requiring more programming knowledge.

Modern engines targeting old hardware keep appearing, and the trend is consistently toward lowering the barrier.

What This Means If You Want To Try

If reading this has made you want to make something, the honest advice is short.

Start with GB Studio or PICO-8. Both are free, both have excellent documentation and large communities, and both let you get something playable in an evening. GB Studio if you want it to run on real hardware. PICO-8 if you want the fastest possible feedback loop.

Do not start with assembly. You can learn it later if you want to. Starting there is how projects die.

Embrace the constraints. Four colours and a tiny memory budget are not obstacles to work around. They are what makes finishing possible, and they are why these games have a coherent look.

Finish something small. The scene is full of ambitious unfinished projects and short of small finished ones. A twenty minute game that works is worth more than an epic that never ships.

You can put it on a cartridge. If it turns out well, publishers do take submissions, and developers routinely arrange their own small cartridge runs sold from their own itch.io pages. Our homebrew publishers guide covers who does what.

Where To Play What Gets Made

Everything discussed here produces standard ROMs for the target system, which means anything that plays that system plays these games.

On original hardware, through a flash cart. Our flash cart guide covers the options.

On a retro handheld, natively. Game Boy, NES and Genesis emulation is within reach of even the cheapest devices, and PICO-8 runs well on most of them.

On an FPGA console or handheld, for accuracy. The Analogue Pocket, ModRetro Chromatic and similar devices run these games from real cartridges or, on some devices, from files.

A huge amount of homebrew is free, released by creators who want people to play it. Our best free homebrew games list is a starting point.

Frequently Asked Questions

What is GB Studio?

A free, open source, visual game creation tool that exports real Game Boy ROMs playable on original hardware. You build scenes visually and define behaviour with a drag and drop event system, so you can make a working Game Boy game without writing code. It is the main reason new Game Boy games appear in volume.

Do you need to know assembly to make a retro game?

No, not anymore. GB Studio requires no programming at all. NESmaker is similar for the NES. SGDK lets you write Genesis games in C, and cc65 does the same for the NES. Assembly is still used for the most demanding projects, but it is no longer the entry requirement.

Was Deadeus made in GB Studio?

Yes, according to widely reported accounts of its development. It is the title most often cited as proof that GB Studio can produce genuinely good games rather than technical demos, and it has had multiple cartridge printings.

What is SGDK?

The Sega Genesis Development Kit, a free and actively maintained C based toolchain for the Mega Drive. It provides libraries for sprites, sound and input, and it is the main reason Genesis homebrew is as polished and ambitious as it is.

Why is SNES homebrew rarer than NES or Genesis homebrew?

Mostly tooling. The NES has NESmaker, cc65 and decades of NESdev documentation. The Genesis has SGDK. The SNES has thinner tooling, a more complex graphics system and a notoriously difficult audio chip, so fewer people get past the starting line.

Can I put my own game on a real cartridge?

Yes. Publishers accept submissions, and many developers arrange their own small cartridge runs and sell them directly from itch.io. Producing cartridges means ordering PCBs, shells and labels in fixed quantities, so it is a real cost, but it is an accessible one.

What is the easiest way to start making a retro game?

GB Studio if you want your game to run on real Game Boy hardware, or PICO-8 if you want the fastest feedback loop and do not mind that it targets a fantasy console. Both are approachable, well documented and have large communities. Finish something small first.