In the year 2134, it has been some time since the last of the world wars finished up. Several years have gone by peacefully, buy now a new threat looms. A threat the likes of which has not yet been seen - one not of this world... Aliens have invaded earth! After a bit of time, a defense was managed to be built. The best tactic for taking out their alien craft just hso happened to be good old fashioned Earth style air defence cannons. There are a few different models of cannon available to use, each of them having their own strengths and weaknesses. When you're at the factory screen of the game, you are able to purchase ammo, upgrade the the ammo storage capacity of your factory, repair or upgrade the factory, and train/assign taks to workers. Your factory will take damage over the course of doing battles, so you will definitely need to make a point to periodically go in and repair things. Later on alien ships will be able to do more damage with each single shot as well, so you will also need to increase the maximum hit points of your factory to counter balance the increased fire power of your foes. And of course, you'll want to increase ammo capacity - those powered up alien ships are bullet sponges that will take a decent number of shots to bring them crashing and burning down towards the ground. The importance of training your works also cannot be understated. The workers you have at your factory will perform various tasks for you and support you on your mission - set them to do things such as working towards your current mission objective or on producing more much needed ammo. Sometimes it's best to have as many workers as possible working on a single task to achieve a mission objective - the faster the mission ends and the factory finishes making a nuclear bomb, the more money you will end up earning. That said you need to be mindful of your defense - keep at least a few workers on ammo production, because the last thing you want in the middle of a fire fight is to run out of ammo and be helpless against the alien invaders.