Demolition Playground
Twelve little structures, three tools and one rule: bring the marked part down, and leave the statues standing.
About Demolition Playground
Demolition Playground is a physics puzzle. Each level is a small structure of wood, brick and steel pieces welded together, with a part marked as the target and one or two protected statues on numbered plinths nearby. You get a few tokens of one tool - pull a support, fire a projectile, or release a wrecking ball - and the physics does the rest.
The world is a real 2D rigid-body simulation (planck.js, a port of Box2D) stepped at a fixed 60 steps a second, so the same moves always give the same result. Welds break when the impulse through them passes a limit for their material, and a run is judged when everything has stopped moving, or after 30 seconds.
How to play
- Choose a level. The tool for it is shown under the structure, with the tokens you have.
- Remove a support: tap an outlined piece, or pick it from the list, then press Remove piece. Press Run when you are ready.
- Projectile: choose a weight, then drag from the launcher or set the angle and power, and press Confirm launch.
- Wrecking ball: pull the ball back by dragging it or with the slider, then press Release the ball.
- You can pause a run at any moment and use another token. When everything settles, the result explains what happened.
Controls
- Pointer or touch: tap a piece to select it; drag to aim. A drag that is cancelled (for example by a scroll) changes nothing.
- Keyboard: every action is a button, slider or number box below the picture. Tab to it; arrow keys move a slider by one.
- Run, Pause, Slow motion and Reset structure are always below the picture.
The rules
- A level is cleared when at least the stated share of the target's mass has come down below the dashed line and no protected statue has moved more than 15 cm or tilted more than 10 degrees.
- Pieces you remove count as brought down. Pieces that start low never count, so a level never begins partly cleared.
- Tools act only while the run is paused or before it starts. Each use spends one token.
- Show a solution plays the stored reference moves. That run is marked assisted and never sets a best.
Scoring, saving and limits
A cleared level scores 1000 times the share of the target brought down, minus 50 for each token used. A run that disturbs a statue is not cleared and scores nothing towards a best. Sandbox runs are not scored.
Your level, the moves of the current run and your best score for each level are saved on this device after every move; on reload the run is re-simulated from the moves, so it comes back exactly. Download a backup to keep it; an imported backup is checked move by move before it is accepted, and can be undone. A challenge link holds only the level.
Twelve levels, four for each tool. The physics is a game simulation with game-tuned materials and joint limits. It is not an engineering model and says nothing about how real buildings behave or how to take one down.
Accessibility
Every action in the picture also has a button, slider or number box, and every removable piece is listed by name. Live readouts give the share of the target down, whether the statues are safe and the tokens used, in words as well as in the picture. Protected statues are marked by number and a striped plinth, not by colour alone.
Questions
- I did exactly the same thing twice and got the same result. Is that right?
- Yes. The simulation runs in fixed steps, so the same moves at the same moments always give the same outcome - which is what makes a level a puzzle.
- What is Sandbox?
- Sandbox lets you use any tool on any piece, as many times as you like, just to see what happens. It is never scored.
- Why did my run stop before everything fell?
- Runs are judged after 30 seconds even if something is still rolling; the result says when that happened.