A free app for Android, by Fakmob LTD.

In Combat Strike: FPS War – Online shooter, you will play as a member of the elite commando squad. Your mission is to complete the mission of the elite commando squad. To complete the mission, you must eliminate all of the enemies. The way to eliminate the enemies is to gun them down or blow them up. You can also use the various weapons that you have at your disposal, such as rifles, machine guns, sniper guns, grenade launchers, and others. 

This has addictive gameplay, so it will keep you busy playing for hours. You can also enjoy the fun and action with your friends in Team Mode.