The game is Called "One Earth". You control a giant mech as it walks around the planet in a 2D plane. You must save Earth from a cartoonish swarm of aliens by building turrets in different biomes (Sand, Ocean, Mountains, and Plains) to defend your home as you make your way toward an escape. Each biome has a different affect on the turret. You can stack them, turn them into shields and more, but BE CAREFUL, using to much of Earth has its own consequences.