Iron Brigade

Trenched is an video game developed by Double Fine and produced by Microsoft Game Studios as a downloadable Xbox Live Arcade title on the Xbox 360. Announced at the 2011 Game Developers Conference by Tim Schafer, Trenched is a hybrid tower defense and third person shooter game, set after World War I in an alternate reality, where the player controls units from "The Mobile Trench Brigade" to fight off robotic species called the Monovision. The player will control giant mecha-style robots with weapon and armor customization through a variety of missions set across the world.

Source: Wikipedia, "Trenched," available under the CC-BY-SA License.