What immediately caught my eye is the art style. Heck, even the itch.io page looks like a charm. From the critical side, I'm sorry that I broke your game. If you keep spawning sand and push the crab to the border of the screen, the crab will eventually fall down to the very bottom. I'm not sure this is intentional or a bug.
Ok, here comes the good side. Which is everything! I so want to download this game, as Kirijo suggested, and use it as a wallpaper! I remembered I played something similar on a mobile device once, I couldn't remember the name of that game, but the general idea is the same, and heck, I couldn't figure out how the algorithms are written. Did you use a certain customized program or is this the particle system w/ physics? - Frank