Alcatraz

In the future the world is overrun by aliens that attack the people. A special group named Alcatraz appeared in the midst of those dark times, with advanced war technology and funding from the governments of the entire world, and protected the world from those aliens coming from a parallel universe. Now they take care of the odd materialization here and there, but a new great threat is arising...
Let me know what you guys think, harsh and critical is good too, and any possibilities of corrections please bring them in, as well as typos XD