Alchemia

Play Alchemia online for free — a pixel art falling sand simulation in your browser, no download needed. This is an alchemist's lab where the laws of physics are your toys. Paint sand and watch it pile up. Pour water and watch it flow downhill. Light a fire near oil and — well, you'll find out. Nine elements, dozens of interactions, and an entire grid waiting for your experiments.

Sandbox mode is pure creative freedom. Build a wooden bridge, set one end on fire, and watch the flames eat across it while ash crumbles into the water below. Pour lava onto sand and see it melt. Drop water on lava and get stone and steam. Pause the simulation to set up elaborate chain reactions, then unpause and watch your Rube Goldberg machine of elements play out tick by tick.

Challenge mode is where the real game lives. Ten hand-crafted puzzles give you a limited particle budget and a goal: guide water here, burn through that, dam this lava flow. Solving them requires understanding how every element behaves and interacts — and doing it efficiently earns you stars and leaderboard bragging rights.