If you get to the treasure room quickly, the level is medium, otherwise nearly impossible.
1st board: Trigger Stone Maker blocks first, then bring down the mystery egg. Hopefully it has a color burst of a color that touches most Diggy blocks (but usually the other). If it fills the Magic Orb, quit - the level is not worth playing then! 30,000 points in Diggy blocks and 18,500 points in gold-striped blocks.
2nd board: Collect gold-striped blocks in the upper left before triggering the Stone Maker blocks. Dont touch the one on bottom left! Use a first Magic Orb on the Diggy Blocks, a second on the steel for a short cut to the exit. 45,000 points in Diggy blocks and 24,000 points in gold-striped blocks.
3rd board: Bring down the upper mystery egg and use a first Magic Orb on the exit, a second on the Diggy Blocks. 73,000 points in Diggy blocks.