If you ever thought Sobokan, Dig-Dig and every other "mine" game looked surprisingly similar, the developers of SubTerra did too, and they have meshed all of these games into one object-filled puzzle.
The gameplay doesn't stray far from the others. Simply stated, you must clear a board of jewels while keeping bad guys away. There are obstacles like boulders or bombs, which you have to manipulate to your advantage.
While not a visual powerhouse, the sprites and levels are well designed. With all the different types of things you can do in a mission, the only boring part is when the demo levels are exhausted.