Many folks use their smartphones and tablets to play games. You are going to enjoy your experience more with a decent gaming controller. AppTrigger Blue offers a whole host of features to improve your games. You can use your voice to call strikes. It has an electromagnetic sensor that recognizes hand gestures (e.g. when you are throwing grenades).
This controller offers realistic recoil and head gesture support. It even recognizes when you crouch. This is a Bluetooth 4.0 controller. AppTrigger Blue already works with Dead Trigger 2 and Call of Duty: Strike Team. It has a SDK for customization of sensors. Like this product? You can support it on Kickstarter.