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Thanks to Kyle Schiller at Marathon Fusion for conversations and information that informed this essay. All errors are my own.

Much of modern civilization is built on top of chemical reactions, either to produce new materials (as in the blast furnace, which converts iron oxide into metallic iron), or to generate energy. Chemical reactions, as we’ve previously noted, work by rearranging how atoms hold their outermost electrons. Combine an atom of sodium and an atom of chlorine, for instance, and sodium’s outermost electron will end up in chlorine’s outer electron shell in an ionic bond, creating sodium chloride — common table salt.

With these sorts of chemical reactions, we’re only shifting around atoms and the electrons that orbit them in the form of chemical bonds. The interior of the atom — the atomic nucleus, which contains an atom’s protons and neutrons — remains unchanged. But if you create the right conditions, it’s possible to rearrange the interior of atoms as well. In nuclear fission, the reaction that powers nuclear power plants, the nucleus of an atom splits, creating several new atoms and releasing an enormous amount of energy in the process. In the fusion reaction taking place within the sun, hydrogen atoms are fused together, their individual nuclei combining to form helium. In particle accelerators like the Large Hadron Collider, charged particles are accelerated into each other using electromagnetic fields, and scientists study the various fragments created by the collisions.

By changing the number of protons or neutrons in the nucleus, these nuclear reactions can create things that can’t be created via conventional chemistry. Change the number of neutrons in an atom, and you get a new isotope of that particular element: an atomic variant of the same chemical, but with a different mass. Change the number of protons, and you end up with a different element entirely, possibly one that doesn’t occur in nature at all.

Typically, the products of these reactions (which we’ll simply refer to as “isotopes”) are unstable: they decay into some other, more stable isotope, emitting radiation in the process, which can be harnessed for various purposes. Carbon dating, for example, relies on the fact that living organisms absorb carbon-14, an isotope of carbon with eight neutrons in the nucleus that eventually and reliably decays into atomically stable nitrogen-14 (the “14” indicates the number of protons and neutrons — carbon-14 has six protons and eight neutrons, while nitrogen-14 has seven protons and seven neutrons). Another process, radiographic welding inspection, uses a variety of radioactive isotopes, such as iridium-192 and selenium-75, to emit gamma rays to inspect welds. Smoke detectors rely on americium-241, an isotope of the artificial element americium — radiation emitted by a small amount of americium causes an electric current to flow across a chamber, but if smoke enters the chamber, the flow of electricity is interrupted, triggering an alarm.

Currently, our use of isotopes is constrained by the fact that creating them is difficult and expensive. Gram for gram, isotopes are some of the most expensive materials on the planet. And the supply chains to produce them are often extremely fragile. Technetium-99m1, a widely used radioactive isotope for medical imaging, is produced through the decay of another radioactive isotope, molybdenum-99. Molybdenum-99, in turn, is produced in only a few nuclear reactors around the world;there was a worldwide shortage in 2024 when some of these reactors went offline for repairs. If isotopes could be manufactured more easily and more cheaply, it could open up numerous possibilities — cheaper medical treatments, better nuclear power sources, possibly even useful new materials.

Making isotopes

We’re all familiar with the periodic table, which lists every chemical element known to man.

Each element on the periodic table has an atomic number, which is the number of protons in the nucleus, starting from atomic number 1 (hydrogen, which has one proton in the nucleus) all the way up to atomic number 118 (oganesson, an artificial element with 118 protons in the nucleus). It’s the number of protons in an atom that makes an element an element — carbon always has six protons, because having six protons in the nucleus of an atom is what makes that atom carbon.

But there are also neutrons in the nucleus, and the number of neutrons can vary. Most carbon on Earth, for instance, is carbon-12, which has six protons and six neutrons. But about 1% of carbon is carbon-13, which has seven neutrons. The most common isotope of helium is helium-4, which has two neutrons, but there’s also helium-3, which only has one. Most of the water molecules in Earth’s oceans are made up of hydrogen with no neutrons (hydrogen-1), but about one out of every 3200 water molecules contains a hydrogen with one neutron, also known as deuterium (water made from deuterium is sometimes known as “heavy water”).

We can visualize isotopes on what’s called a nuclide chart, shown below. The horizontal axis is the number of neutrons in a nucleus, while the vertical axis is the number of protons.

We can see that most elements have several different isotopes, most of which are unstable. Only the isotopes in black in the chart above are stable; everything else will eventually decay. Red isotopes on the chart above decay by what’s known as “beta-plus” decay or electron capture, turning a proton into a neutron. Teal isotopes decay by “beta-minus” decay, turning a neutron into a proton. Yellow isotopes decay by “alpha” decay, emitting an alpha particle (two protons and two neutrons). The rate at which an isotope decays into another isotope is typically described as its “half-life” — the amount of time it takes for half of a sample to undergo radioactive decay. Half-lives can vary wildly, from tiny fractions of a second for hydrogen-5 to hundreds of millions of years for uranium-235.

For isotopes that are stable, or that decay slowly enough that they can be found in the environment, it’s sometimes possible to obtain them by separating them out from other isotopes. But this is often difficult, because isotopes tend to be chemically identical, and most separation methods must rely on minute differences in the atoms’ weights. Much of the difficulty in the Manhattan Project, for instance, was in creating sufficient concentrations of a specific isotope of uranium, uranium-235, that would undergo nuclear fission. Uranium-235 only makes up about 0.72% of natural uranium, and producing a single, football-sized lump of it required a processing facility the size of a small city.

But many isotopes can’t be found in nature at all. There’s no natural source of the technetium-99m or molybdenum-99 used for medical imaging, or the selenium-75 used for welding inspection. It’s thus useful to be able to manufacture specific isotopes.

How do we do this?

At a high level, creating isotopes means rearranging the interior of an atom. In some cases, this happens by natural radioactive decay. The americium-241 used in smoke detectors, for instance, mostly comes from decaying plutonium-241. But for most isotopes we’re interested in, we can’t rely on natural mechanisms; instead, we have to deliberately rearrange atomic nuclei by bombarding them with different sorts of particles. Depending on the sort of particle you hit the nucleus with, the energy of that particle, and the nature of the target atom, you can create different sorts of reactions. These reactions are typically described by the following format: target(input particle, released particle)product. So in 1917 when Rutherford bombarded nitrogen atoms with alpha particles, producing oxygen and hydrogen nuclei (protons), that reaction was N-14(alpha,p)O-17. The figure below shows different sorts of reactions and how they move an atom to a different location on the nuclide chart.

There are a few different ways we can hit an atom with a particle. One is to use a particle accelerator, such as the cyclotron, invented in 1929 by Ernest Lawrence (who would go on to win a Nobel Prize for his invention). The cyclotron uses powerful electromagnetic fields to accelerate charged particles along spiral paths. With his 27-inch particle accelerator, Lawrence could accelerate helium nuclei to roughly 1% of the speed of light.

Lawrence’s first cyclotron, via Wikipedia.

It wasn’t long after Lawrence created his cyclotron that it began to be used to create various isotopes. Naturally occurring radium was already being used to treat cancer with radiation, and Lawrence hired personnel to investigate the potential of using cyclotron-created isotopes for medical and research purposes, such as radioactive phosphorus-32. Phosphorus-32, which has one more neutron than the stable phosphorus-31, was a promising research isotope because organisms naturally incorporate and accumulate phosphorus: if that phosphorus were radioactive, it would allow various metabolic pathways to be observed and possibly allow for highly targeted radiation treatments. Lawrence quickly found that demand for phosphorus-32 for experimental cancer treatments and biological research was “almost insatiable,” and by 1939 a dozen cancer patients had been treated with cyclotron-produced phosphorus-32.

Particle accelerators are still used to produce isotopes today. GE Healthcare, for instance, sells several different medical cyclotrons. The GE PETtrace 800 uses a beam of hydrogen or deuterium nuclei (protons or proton + neutron) to create isotopes such as oxygen-15, nitrogen-13, and fluorine-18, which are then used for medical imaging.

The downside of particle accelerators is that it’s hard to use them to produce a large volume of material efficiently. A medical accelerator costs in the single-digit millions (plus several more millions for the facility to house it) and can only produce about a dust-grain-sized speck of material every hour.

This is due largely to how particle accelerators work. They accelerate particles using electromagnetic fields and so only work on charged particles: electrons, protons, or positively charged atomic nuclei. With electrons, it’s apparently hard to get them to trigger nuclear reactions because they don’t feel the strong nuclear force — electron accelerators thus mostly work by firing the electron into another target and triggering the release of gamma rays, but most of this beam will end up as heat. Because protons or alpha particles are positively charged, they’ll be repelled by the positively charged nucleus of the target, similarly reducing conversion efficiency and creating a lot of heat that must be dealt with. When the PETTrace 800 uses protons to make fluorine-18 (which uses oxygen-18 as an input), only about 1 in 800 protons enters the oxygen nucleus.

Another way to create the necessary particle collisions is to use nuclear fission: unstable atomic nuclei splitting apart when struck by a neutron. There are a couple of ways to leverage this. One is to simply harvest the products nuclear fission naturally generates. Molybdenum-99, for instance, is naturally produced during the fission of uranium-235 and plutonium-239. Strontium-90 is similarly a byproduct of nuclear fission and is sometimes harvested from spent nuclear fuel.

You can also use nuclear fission as a particle source. The fission of uranium-235 releases neutrons, which can then be used to bombard various targets to produce isotopes. Cobalt-60, for instance, a widely used radiation source, is created by placing cobalt-59 in a fission reactor, causing some of the atoms to absorb a neutron via neutron capture.

Using nuclear fission as a source of radioactive isotopes began almost as soon as the first nuclear reactors were created. Long before the Atomic Energy Commission built the first nuclear power plants, it was shipping reactor-created isotopes across the country and around the world for medical and scientific research. By 1956, more than a year before the first US civilian power station at Shippingport came online, there were 50,000 isotope purchases per year from the AEC.

But there are also drawbacks to using fission as an isotope source. For one, fission reactors are highly regulated, and constructing them is difficult and expensive. For another, most of the neutrons produced by fission reactors aren’t particularly high-energy, and in power reactors they’re generally deliberately slowed down to increase the chances that they’ll strike an atom and continue the chain reaction. The average fission neutron is created around 1.5–2 million electron volts (MeV), moving at about 6.5% of the speed of light, but in power reactors they’re slowed down using a moderator to about 0.025 electron volts. And even without moderation, the relatively low energy of most fission neutrons means that many nuclear reaction rates will be slow, and other reactions are out of reach.

To create isotopes efficiently, what we’d like is some way to generate a lot of neutrons at much higher energies. This would make many sorts of nuclear reactions possible while avoiding the inefficiencies of using particle accelerators.

One way to do this is with nuclear fusion. Much has been made about the difficulties of creating a fusion power plant, but fusion has always been a problem of efficiency: getting more energy out of your reaction than you put into it. Creating the fusion reaction in the first place has never been the issue, and fusion reactions have been created in the lab as far back as the 1930s. And these fusion reactions reliably produce high-energy neutrons. While fission can produce high-energy neutrons, only around 0.1% of them will be above 10 MeV. By contrast, neutrons produced when fusing hydrogen-2 (deuterium) and hydrogen-3 (tritium) are 14 MeV or more. Fusion has historically not been used to produce isotopes, but today a variety of startups and organizations are pursuing the idea. SHINE Technologies is currently building a facility, Chrysalis, to create Mo-99 via a complex process that requires a particle accelerator, a fission reaction, and a fusion reaction. Italy’s SORGENTINA-RF program similarly wants to create Mo-99 using fusion-generated neutrons. Marathon Fusion wants to use fusion neutrons to create a variety of different isotopes, such as terbium-149 and actinium-225 for cancer treatments, as does New Zealand fusion startup OpenStar.

Possibilities of cheap isotopes

Beyond its ability to generate high-energy neutrons, fusion also has the potential to make isotope manufacturing dramatically cheaper, at least for some isotopes/reactions. Particle accelerators take a lot of energy to operate: GE’s PETtrace draws about 75 kW, roughly as much as 75 microwaves when it’s running, which sets some floor on how cheaply they can produce anything. At 75 kW, it would take around 0.7 terawatt-hours to produce a gram of fluorine-18, which is around 1.5 hours of the entire electricity output of the US.

Energy costs aren’t actually all that significant for medical isotope production, since the doses are microscopic (600,000 doses of fluorine-18 combined weigh about as much as a single grain of salt). But if you wanted to produce large amounts of isotopes — grams, pounds, tons — it would eventually become a binding factor. And a particle accelerator is essentially only producing isotopes: the isotopes must be priced high enough to recover the costs of building and operating the facility. With fusion, however, your isotope-producing reactions can (potentially) also produce energy — so if you use the right reactions, you could use the sale of that energy to help pay for the facility and its operation.2 It’s conceivable that the right energy-generating fusion reactions, in the right arrangements, might be able to produce isotopes far more cheaply.

What sort of things become possible if we can produce isotopes far more cheaply? There are a few major categories of interest.

Medicine

One of the largest isotope markets, with some of the most expensive isotopes, is medicine. With medical imaging isotopes, a patient is given a very small amount of radioactive material, which gets taken up by the body and (generally) incorporated into specific cells or substances. Fluorine-18, for instance, gets incorporated into a glucose-like molecule called FDG, that the body then absorbs as if it were glucose. By monitoring the radiation released by the isotope, some area of the body or biological process can be monitored.

Medical isotopes are also used for radiation treatment. Some elements naturally collect in certain areas of the body, and radioactive isotopes can be used to deliver targeted treatment. Iodine, for instance, naturally collects in the thyroid gland, and radioactive iodine-131 can be used to treat thyroid cancer. Other isotopes, such as actinium-225, decay by emitting alpha particles, which travel an extremely short distance in tissue, also making them useful for delivering very targeted radiation therapy. A better process for manufacturing these isotopes could potentially allow existing medical isotopes to be made more cheaply and reliably; actinium-225, for instance, is a potentially promising isotope for cancer treatment, but current supplies are so limited that only a small number of patients a year can be treated using it. A better process could also potentially enable the creation of entirely new medical isotopes.

Nuclear power inputs

Both fission and fusion reactors rely on isotopes for various parts of their operation. For fusion, the reaction that creates valuable tritium within the fusion cycle requires an isotope of lithium, lithium-6, which makes up about 7% of all lithium and which currently must be produced via an expensive process of lithium enrichment (which is currently only done in Russia and China). Conventional fission reactors, similarly, require the extremely pure lithium-7 produced by the same process, since naturally occurring lithium with too much lithium-6 would absorb too many neutrons. Some new proposed fission reactors, such as TerraPower’s molten salt reactor, require another isotope, chlorine-37, which is currently only produced by the gram but is needed by the ton. A reliable, cheap source of these sorts of isotopes could thus potentially be very valuable (though as I understand it these are much less valuable than medical isotopes, since they’re stable and can be produced via separation processes, so probably not something we’ll see produced via fusion in the near term).

Nuclear batteries

One of the many nuclear technologies that remain somewhat under-explored is nuclear batteries: a battery that generates electric current using a small amount of radioactive material. These sorts of batteries were used for pacemakers for several decades, and are used to power spacecraft, but with the ability to manufacture better battery isotopes many other uses might be found, such as undersea drones that can stay permanently submerged for monitoring undersea cables.

Materials

In some cases, the nuclear chemistry process might let you make “normal” materials that are otherwise difficult or expensive to get. Marathon Fusion got a lot of attention last year (and last week) for a fusion neutron-driven reaction that can create gold using mercury as an input.

Cheap nuclear chemistry might also allow you to more efficiently make what’s known as “isotopically pure” materials. Most elements found in nature have multiple stable isotopes, and thus any minerals or materials that contain them will contain a mix of different isotopes. Steel, for instance, will be a mixture of several different stable isotopes of iron (iron-54, 56, 57, and 58) and carbon (carbon-12 and 13). But if you could make isotopes very cheaply, you could possibly more easily produce materials entirely using one elemental isotope, such as semiconductors that only contain silicon-28.

In some cases, these isotopically pure materials might have interesting or useful material properties. Isotopically pure diamond has far higher thermal conductivity than regular diamond, for instance (as do, apparently, many other isotopically pure materials). And because of its different quantum-mechanical properties, isotopically pure silicon is useful for building quantum computers.

Historically producing isotopically pure materials has been so difficult that much about them remains unknown; reducing the cost of making isotopes could break open this field of study.

Conclusion

For many technologies, how big an impact they have is a function of how cheap they can get. Solar PV was a niche power generation technology before decades of falling down the learning curve; steel was an expensive material used in limited ways before Henry Bessemer and others found ways to produce it cheaply; Ford’s Model T changed the world not because it was the first car, but because of how cheaply Ford could manufacture it. So a technology that offers the potential to produce some existing thing far more cheaply is always interesting to me, and I’ll be paying attention to see how this develops with isotopes.

Technetium-99m is technetium that’s in what’s known as a “metastable” state, an excited state that eventually decays to regular technium-99, emitting gamma rays in the process.

Specifically, most fusion uses deuterium and tritium as inputs, known as D-T fusion. Deuterium is incredibly common, but tritium is rare and expensive. But you can add a step to the fusion reaction so that it also creates tritium, reducing or eliminating the need for an outside source of it.

I've written before about how November 2025 was an inflection point for coding agents - the point where Opus 4.5 and GPT-5.1 crossed a tipping point that meant their respective coding agents became reliable daily drivers for software engineers. I think we've reached a new inflection point in October 2026, and this time it's for vibe coding computer games.

Claude Opus 5.5 in particular exhibits meaningful improvements in several areas needed to build a compelling game:

3D modeling
Music generation (see Scrimshaw Jukebox)
Game design (!)

That last one is particularly important. Models have been able to create something that looks like a game for quite a while now, as seen in my previous experiments. The challenge has been getting to a game that's actually fun to play.

Game design is a deep subject area. I won't pretend to be well versed in it - I know enough to have respect for it as a craft. Creating a novel, compelling gameplay loop which challenges players at the right level and provides a satisfying learning curve is a fine art. I didn't think the models could do it.

Then I tried telling Claude Opus 5.5 to "Make it a LOT more fun"... and it did.

In the past few weeks I've vibe coded (in the classic sense of the term - no looking at the code at all) four games that I've genuinely enjoyed playing.

I attended Foo Camp in Berkeley over the weekend and met several people who were having similar experiences. Building games that play well is shockingly easy now. The new challenge is coming up with concepts for games that are novel and delightful and that wouldn't exist without AI assistance.

I haven't done an exhaustive study, but my current impression is that GPT-6 Astra isn't quite there yet. It can absolutely build a game, but its sense of fun doesn't match that of Opus 5.5. I expect OpenAI will get there by the end of the year.

Here are the four game projects that have convinced me that the models are now capable of producing fun games with very little guidance. All four are built in HTML and JavaScript and run entirely in the browser.

Tree Appreciator

The smallest game I found to be genuinely delightful is Tree Appreciator. I used the regular Claude chat interface for this - it didn't even need Claude Code.

I built this on a whim while we were driving along Skyline Boulevard looking at trees. My prompt was:

Build a three js game called "Tree appreciator" - it shows you two algorithmically generated trees and the game mechanics is about appreciating the differences between them. Think hard about how to make sure it is both fun and beautiful.

I've found that telling models to use three.js works really well. Claude doesn't have its own image generation model but is capable of building full-color 3D models that look and feel excellent.

This game required no iteration or follow-up prompting at all - I got the game in a single shot. It gave me back a charming little mobile-friendly spot-the-difference game. You can play that here. Here's the chat transcript that built it.

It's pleasingly relaxing. The graphics are fun, and collecting trees that you have completed in a "herbarium" provides a nice, cosy sense of accomplishment.

Emberwick

This was a more ambitious project that I again built using regular Claude chat. I started out by building an experimental prototype of an engine for a top-down fantasy RPG:

Build a demo game engine three.js which is a top down (but at an angle) RPG - the player gets to move through the world with one or two companions. Create a fantasy village setting that demonstrates walking around outside and then shows how when the player enters a building the wall between the player and the camera goes transparent so the user can see what is happening

Add some NPCs and plenty of furniture and different types of building some with an upstairs - be creative, make it look great

Here's that first version. It worked really well!

I was inspired to increase my ambitions:

Make it not so flat - the buildings are great but the landscape itself is completely flat at the moment, fix that

Add basements to two of the buildings with a tunnel system joining them below the village

Add the start of a rocky mountain on one side of the village containing a cave with a sleeping troll

Here's that version.

When that produced a good result, I decided to push it all the way:

Now turn this into an actual game - quadruple the size of the playable area, introduce fun game mechanics, add a plot that isn't too cliche, some twists, a magic system, make it really good

We're back to prompts like "make it really good" here! Asking for a plot that "isn't too cliche" seemed to work too - it's a bit cliché, but still novel enough that I enjoyed following the story.

Unlike Tree Appreciator, this took quite a bit of additional playtesting and prompting to get to a finished version. This was mainly due to gameplay problems - things like a character not being in the right place to complete a quest because a different story element had caused them to move to another location.

Here's that final game. It has a full story that takes about 15 minutes to play through.

There's even an experimental level editor if you want to drop in your own houses, furniture, and landscape features.

Once it was all working (and I'd iterated through some gameplay bugs), I played it through from start to finish and found myself emotionally affected by the ending! I'm somewhat embarrassed by this, because everything in this game - the graphics, the plot, the characters, the music, the dialog - came from the model. My creative input was pretty much just "it's a fantasy village and there's a troll asleep in a cave".

Here's the full shared Claude chat in which I built this game.

I also fed that same initial sequence of prompts through ChatGPT GPT-6 Pro. Here's the transcript and the finished game for comparison. It looks great, but I don't think it plays nearly as well.

Battle Drones

This is by far my most successful project, which I wrote about last week. It's a Command & Conquer-style Real-Time Strategy game where two robot armies (or four as of Saturday) build units, harvest scrap, and battle over territory.

This is also the project that convinced me that Opus 5.5 knows what "fun" is.

The first versions were built back in July using Claude Fable 5. It got me to a workable 2D Command & Conquer-style game, but it wasn't great to play.

I prompted Opus 5.5 to "Make it a LOT more fun" and then later to "Port this game to three.js" and the game was transformed. There's a blow-by-blow account (prompts included) in my write-up.

Today, Battle Drones has 2-4 player multiplayer (via a vibe coded WebSockets relay server), medals, replays, seven maps, a random map generator, and a set of "mutators" that add variants of the rules.

It also lets different LLMs play against each other, using a mode where the game advances five seconds and then pauses to give different models time to interpret the new game state and line up their next set of commands. Here's a replay of Claude Haiku 5.5 vs. GPT-6 Luna:

Battle Drones is a particularly good example of Opus 5.5's ability to create 3D models. This page lets you browse all of the models in the game.

I released Battle Drones under the Apache 2.0 License last Tuesday. On Wednesday Gabriel Turpin released Panache (screenshots here), a fork of Battle Drones that reimagined the game for steampunk 1900s Belle Époque France, with new models and music and an animated intro sequence. Open source at work!

Pumpkin Farmer, aka Quarter Sun Cove

I live in Half Moon Bay, California, home of the annual Half Moon Bay Art and Pumpkin Festival, which includes a giant pumpkin weigh-off competition.

I decided to try building a game that wasn't just a cheap imitation of something that already existed, so I set out to create a game about farming pumpkins, growing giant pumpkins, and handling the rush of the October pumpkin season.

I called it "Quarter Sun Cove".

I'm still iterating on this project, but it's shaping up quite nicely. It's a cosy farming simulator where you spend the year tending to your giant pumpkin and planting out regular-sized pumpkins for sale in October, then sell pumpkins during pumpkin season and enter your giant pumpkin in the weigh-off.

Every character in it is a (vegetarian) animal. The mayor of the town is a pelican. You can be a pelican, skunk, raccoon, possum, beaver, coyote, fox, owl, sea otter, or harbor seal. Those species all later show up (accompanied by their children) to buy pumpkins from you.

It's absurdly cute.

You can play the latest version here. I'm not convinced by the game mechanics yet - it's actually quite complicated: you have to decide when to plant pumpkins such that they will become ripe at the weekends in October with the most visitors.

Here's the initial brainstorming session, which resulted in this spec file. Then I had Opus 5.5 Ultracode burn millions of tokens and nearly two days building it.

I told Claude to "surprise and delight the user frequently" and the result is so many little details and easter eggs. There are mischievous raccoons, an elephant seal that runs the weigh-off, harbor seals that roll their pumpkins back into the ocean, a wandering goat, and superstitions about growing giant pumpkins that sometimes come true.

This isn't my best game yet - it's not as fun to play as Battle Drones - but it represents the kind of game I want more of: weird, fun, uniquely personal - something that wouldn't have been built in the before-times.

Four times as insulting

If you are offended by AI-generated art, AI-generated music, AI-generated writing, and AI-generated code, I have bad news for you: vibe coded games combine all of those at once.

I respect those opinions, even though I don’t strongly hold them myself.

The wider games community already has an aversion to AI-generated assets in games. This has been a growing issue over the past few years as tools like Midjourney have enabled developers to generate assets for their projects. This IGN story covering complaints about slop in Valve's Steam Next Fest is a good recent example.

We now have games where everything - code, assets, dialog, and even the game design itself - can be outsourced to the models. And the results don't suck!

Building a computer game used to be one of the most challenging projects in all of software development, combining a diverse range of skills and requiring intense focus and effort over many months or even years. And now here I am spitting out a playable multiplayer RTS by prompting on my phone!

I expect that, as we've already seen with programming, this will result in a split. Some players will refuse to have anything to do with games that were built in this way. Others may embrace this as opening up game development to a much wider audience. I lean in that direction!

I certainly won't be entering any of my vibe coded games in traditional game jams or competitions - I don't feel like I've earned that right. We'll likely see new avenues emerge for vibe game developers to compare their projects.

What happens if someone actually puts the work in?

The thing I find both exciting and shameful about this is that I have got interesting results from so little creative input. The projects I've described here are loosely ordered by how much effort I've put into them. Not a single project represents more than four hours of my work (plus many more hours of Claude Code churning away by itself).

Now imagine what could be achieved by anyone who takes this seriously, invests significant creative time, applies better taste in game design, and then playtests and iterates on the result until it's as good as they can make it.

I want to see games that wouldn't have existed without these new tools.

You should build a game!

Building games in this way is so much fun. It's the perfect application for vibe coding because it's so low stakes: how much damage can you cause with a bug in a personal vibe coded game project?

(OK, you can do some damage... my attempt at audio-based multiplayer gave my wife Natalie a nasty headache!)

All of my games so far have been HTML and JavaScript using static hosting (generally GitHub Pages or Cloudflare Pages). Modern browsers - including mobile browsers - are incredibly capable. Frontier models already know libraries like three.js and Phaser. I'm finding these mobile web games to be indistinguishable from the native experience, at least for the kinds of games I'm trying to build.

I suggest starting with a prompt like this:

Build a mobile-friendly three.js game where...

This works on both chatgpt.com and claude.ai - you don't even need to fire up a full coding agent. As one last example, here's "Build a mobile-friendly three.js game where a mouse has to hide from a cat" by Claude Opus 5.5 Extra and by GPT-6 Extra High.

Switch to Codex or Claude Code once your project passes the proof-of-concept phase.

And if the game isn't fun enough, add this:

Make it a LOT more fun

Tags: game-design, games, ai, generative-ai, chatgpt, llms, claude, vibe-coding, claude-code

# SHOP AND PATREON

# POTTERY

# THE END & WORK AVAILABILITY

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Our verification loop

feedback tool

Explore (raise ceiling) vs exploit (raise floor)

1.

2.

3.

4.

Making isotopes

Possibilities of cheap isotopes

Conclusion

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Tree Appreciator

Emberwick

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You should build a game!

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