Madfinger Games has more and more zombies to kill, as they've demoed Dead Trigger 2 at GDC 2013. The gameplay is largely similar to the original, where players take on new types of zombies in a variety of new environments, like a sandy city, dank sewer, and a ruined city. The city really shows off the improvements to the graphics that Madfinger appears to be going for as a giant zombie that can be attacked with one of the new fixed turrets can be fought.
With the rumors of an official Apple controller, it's a good guess that Dead Trigger 2 to support it, as multiple Android controllers are supported by both this and the original Dead Trigger, with the sequel playable on Nvidia's Project Shield Android device with a gamepad, despite their desire to keep much of the game secret when we met with them. Dead Trigger 2 should be available later this year, and will launch as a free-to-play title.