Created a Flappy Clone dubbed Flappy Ghost to familiarize myself with SpriteKit and the Game template in Xcode. It does exactly what you think it will and works how you would expect. I found the concept of adding physics to make the simple game really intriguing.
To make the game potentially better would be to make it increasingly harder to pass the walls once a certain score is achieved. Also adding music and sound effects would bring this game to life more as well.
I highly recommend following Jared Davidson's Youtube channel as a great tutorial resource and reference for iOS related things!