In year 2222, people invented a portal. In year 2281, the first habitable planet is found. Its colonization is made through portals and it turns out that humans are not the only sentient race in the universe..
To Protect the Earth from alien invasion, you're given a ship class AT-021. But unfortunately the Earth doesn't have enough resources to supply new arms to the ship. Improve the ship by collecting weapons through battles and buy turrets to defend.
