Been going through and playing all the dragon-related games I can find. (Fewer than expected, but more than I thought yesterday) Like others said, this one reminded me of Dig Dug, but with MUCH MORE UNSTABLE ROCKS. I died almost instantly in my first game because I was planning to wait under the rock for a knight to move close, but the rock fell instantly, crushing me.
Once I got the hang of it, I finally died because a rock was hidden behind the score in the upper-left, and I didn't see it until it had already crushed me.
Still, high marks all around, and a very fun game!