Set in the near future, you are "Green," a rookie in a corps of freelance tank commandos called "Da Wardenz." If it sounds like some West Coast rap group, it's supposed to. "Da Wardenz" is comprised entirely of African-Americans, an ethnic group not often represented in popular videogame culture. This gives Shellshock a different style than most shooters, and is one of the game's most interesting features.
The most difficult aspect of the game, learning to drive the tank, when given some time, becomes the most rewarding. The tank responds much like a real tank would, which means it's slooow. If the game's controls were badly designed, it would be an extremely frustrating experience, but as it stands, there's still somewhat of a learning curve. Once mastered, Shellshock is very rewarding.