Many improvements, additions and fixes are in.

Solemn Sandbox

A serious environment to carry out silly experiments.

Solemn Sandbox is an experimental physics, creature-building and artificial-evolution playground where you create things, give them a goal, and see what happens.

Build a creature from joints, bones and muscles. Give it feet, wheels, wings, gliders or parachutes. Drop it into an environment, choose what you want it to accomplish, and let evolution attempt to figure out the rest.

Instead of directly programming your creature to walk, jump or fly, you can give it a neural-network “brain”. A population of different brains attempts the task, the more successful ones are selected to produce the next generation, and over time strange — and occasionally surprisingly effective — behaviours can emerge.

Sometimes they learn.

Sometimes they fail spectacularly.

Both are part of the fun.

Build. Train. Experiment.

The basic loop is deliberately simple:

Build a creature → choose a goal → evolve → watch the best attempt → change something → try again.

But there is a lot hiding underneath that loop.

You can build your own creatures or start with presets, then train them for different abilities including:

• Walking and running
• Maximum speed and sprint courses
• Staying upright
• Jumping and long jumping
• Hang time
• Repeated hopping
• Obstacle and rough-terrain movement
• Climbing
• Wheeled movement
• Ramp jumps and gap crossing
• Flight
• Gliding
• Parachuting
• And more

The creature builder isn't only cosmetic. Shape and structure matter. A badly designed creature may be almost impossible to train, while a small structural change can completely alter what evolution discovers.

You can even allow aspects of the creature itself to evolve, experimenting with changing proportions and physical traits or, at the more extreme end, allowing evolution to grow and prune parts of its structure.

Build the experiment too

You aren't restricted to the supplied environments.

The Environment Builder lets you create your own courses using terrain, boxes, ramps, stairs, pits, loops, launch pads, towers and other obstacles.

Start lines, checkpoints, finish lines, landing areas, reward regions and penalty regions can turn those environments into actual experiments and challenges.

That means the question doesn't have to be:

“Can this creature learn to run?”

It can become:

“Can this ridiculous six-legged thing learn to get over the ramp, clear the gap, hit the checkpoint and reach the finish?”

Then you can change one variable and find out what happens.

Evolution you can actually watch

One of the main ideas behind Solemn Sandbox is that the learning process itself should be interesting.

Press Evolve and you'll see multiple candidate brains attempting the problem. Successful behaviour is selected and mutated into new generations while you watch.

You can keep things simple and let the defaults handle everything, or start digging deeper.

Experiment with how many brains compete, how long each attempt lasts, how adventurous mutations should be, which creatures get to breed, whether evolution should gradually settle down and fine-tune its solution, or even start a new experiment using a previously trained brain.

You can alter what matters to the scoring system, train abilities in stages, race against previous records, introduce slightly different bodies into the population and inspect detailed statistics, rewards, neural-network activity and training telemetry.

You don't need to understand genetic algorithms or neural networks to play with any of it.

But hopefully, after playing with it for a while, you might accidentally start understanding them.

100 hidden discoveries

Experiments can also unlock 100 secret discoveries spread across movement, jumping, flight, climbing, motorised creatures, precision challenges and stranger achievements.

They're recorded in the Trophy Room, so simply messing around, attempting unusual designs and trying things that probably shouldn't work can lead to discoveries.

In other words: breaking from the obvious solution is encouraged.

And then things get sillier...

Solemn Sandbox isn't intended to be a laboratory pretending not to be a game.

There are deliberately less sensible places to experiment too.

Disco

Load music and make creatures react to it.

Audio can influence muscle groups, multiple dancers can perform together, and creatures can even learn dance behaviour from music and recorded movement before refining their own freestyle behaviour.

Yes, you can train an artificial neural network to make your physics creature dance.

No, this was probably not necessary.

Head-to-Head

Save successful creatures and put two trained models against one another in timed head-to-head trials.

Which raises the obvious question:

Whose ridiculous creature is actually better?

Boxing

Because apparently the previous question wasn't enough, Solemn Sandbox also includes a dedicated boxing skill.

Build eligible fighters, mark gloves and target areas, train boxing brains through sparring and put them into timed points matches measuring hits, power and accuracy.

Science.

Probably.

Share what you create

Solemn Sandbox is beginning to grow beyond a single-player experiment.

Trained creatures can be shared using public links, allowing another player to open your creation directly in their own Solemn Sandbox.

Creators can also choose to publish their trained models to the Public Creations library so other players can discover and experiment with them.

I'd love this to eventually become a much bigger part of the project — sharing creatures, experiments, challenges and weird discoveries rather than everybody simply playing in isolation.

This is VERY actively being developed

Solemn Sandbox is not a finished game that I'm putting online and walking away from.

I'm currently working on it and updating it pretty much every day.

Features are being added, systems are being changed, rough edges are being fixed and quite a lot of the direction is still open to change.

That's also why I'm putting it in front of people now.

I don't just want bug reports.

I would genuinely love:

Ideas. Suggestions. Playtest results. Experiments. Criticism. Weird creature designs. Things you don't understand. Things you hate. Things you love. Things you expected to happen but didn't. Features you wish existed. Challenges you'd like to create. Unexpected behaviours you discover.

If you find a creature that learns something particularly well, share it.

If you create something completely useless but hilarious, share that too.

If you think a system could be dramatically better, tell me.

The long-term idea

I'd love Solemn Sandbox to grow into a community-driven experimental playground.

Not quite a traditional game.

Not quite an educational tool.

Not quite a physics simulator.

Not quite an AI laboratory.

Something somewhere in the middle of all of them.

A place where somebody can spend five minutes making a stupid creature fall over repeatedly, while somebody else spends hours experimenting with neural networks, evolutionary strategies, morphology, physics and training parameters.

And perhaps the person making the stupid creature accidentally learns something along the way.

That's really what I'm aiming for:

A place to build things, break things, evolve things, share things, ask “what if?”, and have fun finding out.

Solemn Sandbox

A serious environment to carry out silly experiments.