Hello, I'm an expert in Unity 3D engine and I have been developing games for 2 years. I can build your desired games for any platform(PC/iOS/Android etc) that you want using Unity engine quite efficiently. I would like to discuss about the game further for better development purpose and gameplay, could think of various weapon and game mode but need to clarify your requirements on my end to deliver an excellent piece of game.
Please knock me anytime if you want to discuss further about the game. Have a good day!