In Decision you find yourself in a city packed full of zombies. Kill as many as possible while gaining territory and capturing buildings. As you play the game you can upgrade your weapons and abilities which will help with your progress. The controls are a little unusual so make sure you check them out at the start of the game. They are basically as follows: Use the mouse to move and aim, space to hold your position, W&S to change your distance and A&D to strafe around corners.