Heads up for the creator: there is a version of this game posted on the Google Play store called "sand block color puzzle" by Trang Gaming. Not sure if that was you that put that up, but you may want to look into it.
100K downloads? I feel out of touch, the way these things become popular. Looking at it, I don't think there's any grounds to get it taken down under. Game mechanics aren't copyrightable and it hasn't stolen any assets. They even changed the shape of the T block, presumably to weaken any potential claims from The Tetris Company for trademark infringement.