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Some fun things to try:

- Paint sand and then hit it with lightning - it turns to molten glass and cools transparent!

- Drop "Orbies" (Orbeez) onto water and watch them swell and grow.

- Connect Mortars (fireworks) with a fuse and light the fuse for a personal fireworks show.

- Heat popcorn kernels until they burst into fluffy popcorn and steam!

- Wax behaves like a lava lamp: melts, rises, cools, sinks.

- Drop some metal into a pool of acid, and ignite the fumes!

- Play with gravity, emitters, collectors, vehicles, wheels, rigid bodies, elastics, PNG-as-material imports, fun visual styles, session recording and playback, and more!

SunaBox is a from-scratch rebuild of OE-CAKE, the popular 2008 physics toy that effectively fell off the radar. I've included a Classic mode that recreates the original interface, and it even supports the same .oec files people made fifteen years ago.

Drop any PNG in and it becomes matter. Light a fuse and watch it carry fire to your nitro-bomb!

A more feature-rich version of the game will be coming soon to Steam, if you'd like to wishlist and support this project.

Nitty-gritty about the project:

Some of SunaBox's features are only possible due to SunaEngine: an open source, cross-platform bit-deterministic WebGPU particle physics engine, also made with Fable 5: https://engine.sunabox.dev

This engine/game started out about a month ago as an idea for a data encoding format. I was experimenting with storing data in images and movies with Claude, and suddenly it struck me: "What if we could store data within the various reactions of a particle physics engine, like Powder Toy / OE-CAKE?"

It occurred to me that between the various kinds of materials and the way they interact with each other, a lot of information could be stored in a recorded physics sandbox gameplay session.

What I didn't know was that this was basically impossible with a typical physics sim, which usually relies on floating point math to calculate interactions between particles (long decimal numbers where the end is rounded off). This slight rounding error introduces chaos into floating point simulations; which makes most particle simulators impossible to encode data with!

There's another layer of chaos introduced in the way that different GPUs calculate physics interactions, with different GPUs delivering solutions in different orders.

SunaEngine solves this in a novel way by using integer-based, bit-deterministic physics, and accumulates the solutions in the correct order before rendering a frame- it's been tested to be consistent across NVIDIA(RTX 2070S), ARM (Steam Deck), Apple Silicon, iPhone, and Intel integrated graphics.

It sounds simple, but there's not much like it out there, and I've made it open source for everyone to build with.

And of course, it's not limited to 2D; SunaEngine can be used to build 3D games too.

This actually unlocks some **REALLY** cool potential applications

1. Low latency, cross-platform, multiplayer physics: When all of the GPUs compute physics in the exact same way without variance, only player inputs need to be streamed over the network in order to have accurate, fast multiplayer physics games.
2. Session capture, smooth rewind, and playback - session captures can be saved in very small file formats, replayed on anyone's machine, smoothly scrubbed through like a movie in forward and reverse, and will always render exactly the same, no matter which device you play it back on. (Unless you interact with the scene mid-playback, which is also possible)
3. Research and world models: SunaEngine was built for SunaBox which is, essentially, a toy - but, it can be tuned to more closely resemble real-world physics. With realistic physics and bit-determinism - research simulations can be easily saved and reproduced for inclusion with whitepapers. Predictable, small formats for environments in which to train world models.

I'm happy to answer any questions about the engine, game, build process, etc.

Up front, since this sub rightfully cares: The engine was written in collaboration with AI, which I'll take questions on happily; the proofs however are all real and verifiable:

SunaEngine (AGPL): engine.sunabox.dev / github.com/DARIENBATHALTER/sunaengine

It's a particle physics engine that relies on integer calculation rather than floating point, plus order-independent accumulation, in order to always deliver the same result on any GPU. Three live proof demos on the site, all simulating on your GPU, all hashing their entire state as you watch:

1. The Twin Simulations: two independent sims, same scene, same input schedule, never communicating. Stir either one with your cursor; your input is quantized to substep indices and fed to both. The 256-bit hashes stay identical, interaction after interaction.
2. The Pachinko Proof: an ordinary float solver runs the same pachinko machine twice. One pane adds contact forces in ascending order, the other descending. That is exactly the difference two GPUs or two drivers introduce on their own. The balls never finish in the same bins twice. The integer engine runs the same machine to the same digest, loop after loop.
3. Recording, playback, and smooth rewind: particle fluids cannot be rewound in floating point. Chaos amplifies the last bit of every velocity in reverse too. Here you stir a pool, it records your inputs, verifies the replay byte for byte against the run you just performed, and then hands you a scrubber. Drag your own splash backwards through time.

Replay hashes verified matching across Apple M series, an iPhone, a Steam Deck (AMD), and NVIDIA (RTX 2070S).

There's also a live 3D water demo on the site (Figure 3), same fixed-point solver one dimension up.

Recordings export as lightweight .sunar files, which store only the initial state plus your inputs. They scrub back and forth smoothly like video and play back bit-identically on any device.

This has the added benefit of enabling low-latency, cross-platform multiplayer physics. If every machine computes the same world, multiplayer needs only inputs over the wire.

I built a free-to-play sandbox using the engine called SunaBox (sunabox.dev) which serves as a clean-room reimplementation of the Prometech's classic OE-CAKE from 2008, a particle physics toy. The OE-CAKE interface is recreated 1:1 if you select "Classic" mode at the top, and imports the original .oec files. Still working on parity, but approaching 100% all the time. If I had to estimate, I'd say they work at about 93% parity right now.

The workflow is very simple: I came up with the ideas and tuned the feel of everything by hand and spoken word; Claude did the math, the code, and the adversarial review. Happy to answer anything!

This is Geode, a 3D file explorer experience that puts you in the cockpit of a polygonal cruiser, allowing you to soar and barrel-roll your way through your hard drive in stylish, non-euclidian fashion.

Inspired by a piece of lost software I loved from the early 2010’s, during the peak of the “3D Desktop” craze. Can’t find it anymore, so Claude and I rebuilt and modernized it a bit.

It’ll preview most common filetypes and play music in a folder as a playlist while you fly.

EDIT: Press "L" for a fun surprise, and press "O" to adjust the surprise level!
(Just for fun, does not delete anything!)

Try it (Desktop only):
https://geode.gnatgpt.app

Repo, have fun!
https://github.com/zhvhmvrhlmt/Geode

Controls-

Mouse - control direction
W/S - accelerate/reverse
A/D - strafe left/right
Q/E - barrel roll
Shift - boost
Left click - interact / auto-fly to target
V - sort view (list, grid, orbit)
B - sort order (a-z, size, recent)
L - surprise mode
O - surprise intensity

I've spent the last few months building Card Knight: Astral Arcana; a real-time, grid-based card RPG (Mega Man Battle Network's soul, in a new fantasy skin) and it was just approved on Steam. Surreal. You can go and wishlist it there. It's a real product.

Building was completed 100% through Claude CLI using only conversational direction, with an AI-powered creative API pipeline - GPT-image-2 generating sprites and other visual assets, ElevenLabs providing placeholder voices and filter effects (I voiced all of the characters), and music generation through Suno.

Claude built a few tools for me, a map editor, a dialogue editor, and some tools for me to make manual positioning/alignment calls on many of the sprites.

AI got me 90% of the way, fast — and the last 10% was entirely taste, and still takes a long time. That last bit, of tuning, testing, human-in-the-loop feedback is what makes an AI-driven creative project like this feel alive IMO.

Where it was incredible: generating concept art, scaffolding systems, taking my stream of consciousness feedback and turning it around into code at 1am. 

Where it absolutely couldn't carry me: making the battles *feel* good, pacing a story, creative subjective preference calls, and *really specific artistic needs*.

No AI can generate 8-directional movement sprites, or animated talking/blinking sprites reliably. I tried many ways, and the consistency even with the best (nano banana pro and GPT-image-2) was not good enough. So, all of the portraits and directional movement sprites were hand stitched in photoshop.

I art-directed every asset and playtested obsessively, I think that's the moat, and it's still 100% human.

Happy to get into the actual stack/workflow (pygame) and how I keep a project from feeling like slop. AMA!

Card Knight is coming soon to Steam Early Access and is available to wishlist now!

EDIT: I’m looking for playtesters! DM to try the first ~2hrs of gameplay.

Just wanted to share my own take on a card battler!

Grew up on the PET, nothing since has quite scratched the itch, so a few months ago I started building my own.

Card Knight is my take: keep the chip dodging, folder-building soul of Battle Network, but with a fresh coat of fantasy and HD-2D graphics.

It's 0% roguelike; a fresh world, new story, fully voiced characters, and decks you keep and tune as you go. The cards are as central to the story as chips are in Battle Network.

The clip is straight gameplay; I have about 2 hours polished and am close to completing “Act I” of the story. I'd genuinely love to hear from BN folks: what would make or break a game like this for you ?

Happy to answer any questions! Thanks for taking a look.

EDIT: Disclosure: As stated my Steam page, many of the art/sound assets and code in CardKnight are generated with AI tools, under my direction. The game is conceptualized, directed, and tooled by myself alone. If CardKnight is successful, I pledge to bring a team of all-human talent to produce the sequel.

EDIT 2: I forgot to mention- I am currently seeking playtesters for Card Knight. If you would like to play the story so far (~2 hours); please send me a DM.

Card Knight is currently “Coming Soon” to Steam Early Access! If you’d like to keep up with the project, be sure to wishlist us on Steam.