A free program for Android, by AZUR INTERACTIVE GAMES LIMITED.

In Robot Warfare: Mech Battle 3D PvP FPS, you can assemble your own garage of robots with unique abilities and weapons and win your enemies in dynamic 6v6 battles! There are more than 25 robots to choose from, each with its own unique abilities and weapons. There are a variety of maps to play on, as well as a unique gameplay experience that allows you to play as a lone wolf or team up with other players in online multiplayer battles. 

The game is completely free to play and all gameplay items can be obtained by defeating enemies or winning the game’s weekly events.