GTA: Penguin Massacre
A penguin a place, where there is lots of food. He makes the place his own turf, thus, he is willing to protect it from anyone on any cost. He fortified it, so no one can get there. However, other penguins become envy and soon come barging in on his territory. You need to protect your territory from other jealous penguins, who want to steal the place. Shoot anything that you would see. Each kill would earn you money and you can use it to buy better weapons, repair barricade or even hire another penguin. The game gets harder and harder as you make some progress, so don't forget about upgrading.