I liked the graphics (albeit kinda "noisy" - falling sand particles on the background were a bit distracting) and sound effects.
The gameplay is hectic, and I like it. The character feels slippery a bit but it seems like a positive contribution to the gameplay.
The only thing missing for me was an in-game explanation about the cracks (I had to read the game page to get that), as stated in another comment. Perhaps a hint above the first crack would help.
Also, a minor nitpick: maybe replacing "Game Over" text with something like "Time Out" would help a bit as I was confused why the game had ended (I thought it was because of me being hit by the rocks, but there's no health bar as I can see).
Great take on the theme and a nice little time killer!