Cinderbox

Cinderbox is a short 2D heat-and-coal puzzle built in Godot 4. Keep the fire alive, manage scarce coal, and clear compact puzzles aimed at desktop and browser play. Free HTML5 demo on itch; full Windows + Linux build is $8.99 on Gumroad. From Quarrykit.

How to play

Push living coals onto the grate before they go cold. Get at least one living coal onto the grate; the win is checked after cool/ash resolve.

Controls

• Arrows / WASD: walk / push
• Z or U: undo
• R: restart level
• Enter / Space: advance after a win
• Phone (coarse pointer / narrow viewport): swipe to push; use on-screen Undo / Restart / D-pad

Rules

• Invalid moves spend no turn.
• After a successful walk or push, every coal not moved this turn loses 1 heat.
• Heat 0 becomes ash (an immovable blocker).
• Pushing a coal onto another coal stacks heat; the stack counts as moved and does not cool that turn.
• A heat-1 coal left unmoved on the grate becomes ash and does not win.
• Keep pushing a coal and it never cools heat is a detour budget.

Three tutorials, then twenty puzzles. Stock Godot 4 HTML5 export; no custom index.html shell.