In this game you should drill all the way down to large oil source. You can upgrade your Oil tower and drill. There are enemies - High-Tech autonomical drills from another country that will try to stop you from reaching your goal. You can buy a gun and destroy those enemies or just make some manuevers around them to dodge their attacks. It's 2 AM and I probably need some sleep because I need to go to university tommorow, so have fun everyone playing this game!