Part incremental game, part art project. You buy upgrades which alter the hypnotic progression of the circles in the simulation. It's kind of a screen saver that you progress through. The whole process is only a few hours.

Falling sand idle is an incremental game powered by a little physics simulation.  Your progression is determined by the interactions of lots of little circles that run into each other.  You can make them bigger, smaller, or hotter.  You can change the environment they move around in.  Eventually, they can eat each other.<h2 class="bb_tag" >Content</h2><ul class="bb_ul"><li>Level 1:  You start out moving grains of sand through an hourglass.  Each time a grain hits the bottom, you get it back, and can drop it again from the top.  You also get a tiny moment of time, that you can use to buy upgrades.  Eventually, you'll have thousands of grains on screen at once.</li><li>Level 2: The next level is a forest.  You start out placing leaves, which costs nothing but a click.  You get a tiny adaptation of evolution for every particle you create, which lets you research upgrades.  Eventually, your leaf dies, leaving behind a dead leaf particle.  Once you teach the leaves to reproduce, you'll eventually have too many dead leaves to make new live ones.  Luckily, bugs love to eat dead leaves...</li></ul>

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Falling Sand Idle Achievements