There was a time that the game flappy bird is such a hit, it's popular for its difficulty, but also lose the charming when it's too difficult for most people, they try it for fun but ended with over and over failure, the gap seem to narrow to pass, now in flappy gunner, you can open that gap by your own, a bird with gun! cool, isn't it? you can shoot the tree down, and pass it easily, pick up the items in your way, it may give you a new effect. Have fun!