A cloud floats from right to left on the top of the map. Tap the screen to spawn one of them, based on the location of the cloud. Upon dropping down onto the beam, they exert a force on the beam, which changes the slope of it. The beam also exerts a force upon the crawlers, thus the crawlers move as the beam wobbles. Similarly, dropping more crawlers also impacts the beam and previously placed crawlers. There are collision physics between crawlers, meaning that you can accidentally knock one off with another. A level is successfully completed when all crawlers are placed upon a beam, and a 3 second countdown is completed. If one crawler falls before the countdown finishes, then the level is not completed.