I decided not to go with the obvious interpretation of digging. Instead, you are a soldier whose country is sinking deeper and deeper into debt. At your general's command, you are launching a one-man invasion of a neighbouring country, plundering their precious resources in order to pay off your national debt.

As you drive deeper and deeper into enemy territory, there will probably be some kind of unfolding storyline... but first I have to make a playable game out of this.