In the future, resources are not abundant, so everyone is fighting for it. Everyone wants to live and they would do anything to live. Even if that means kill someone to get their resources. People need to eat, but the food is not enough for all the people. Some people paid a huge sum just to eat, while the rest becomes a bandit and started stealing some food from the rich. The rich would not let their hard earn money to be stolen and as such, they have employed you to get rid of the bandits. The bandits are very persistent and began using some monster trucks to get to the capital where there are lots of food.
So, whenever the citizen see some monster trucks, they know that the bandits are there to get their food. They know that there is not enough food for all and they would be hungry if the bandits grab a hand on their food. They would be crazy to give it away without fighting for it. Though, they are not the ones fighting as they hired a mercenary to do that. Armed with everything that you can see, you are able to hold them back.
The game is played with a mouse and the idea here is to keep those monster trucks at bay. You would just be using a hand when you are starting and would be earning money on each starts that you grab. The stars come from the blown trucks as you smashed them in the concrete road. The game would be harder and more difficult as you make some progress. You need better weapon against the trucks and you can use the money to buy better weapon. Expect things to be harder and more challenging as you move forward in the game.