If you ever played Lemmings or Worms you will have an idea of how this game functions but this game takes the concept so much further. You have full realtime control over all your characters and instead of simply starting with all the weapons or tools you must first dig through the ground to find ore and bring it back to your base to sell it. Then you can purchase new items or even build structures like elevators to assist in moving resources around. The number of items and different resources in this game is amazing. It is very easy to spend hours just exploring all the different possibilities!
The game is now freeware