Very nifty, I really like it!
The controls are easy to get a grasp of, and it's a nice mind game to figure out the sequence you need to do things in. Each of the stones felt like their placement in each level had been thought through, and I liked the introduction to each of the stones happened over many levels.
Had an issue on Level 5, where I fell into the gap where you're supposed to put a box, and couldn't get out - fortunately I can play all the levels from the start, so I just refreshed :)
Overall, I think it was very well executed, well done!