MetalWars 2 (iPhone, iPad)

The best machine action game : MetalWars

*TOP 100(GAMES) - Japan

Metal Wars is Full 3D Shooting Game that attacks and destroys enemies while upgrading to various parts of bots and using variety of weapons.
Not only can you destroy enemies on your own but can also be played alongside other players
You can create your own machine by assembling parts and weapons that you earn from each stage.