Adding a scrolling background/ having alternate backgrounds for successive tries would help add to the variety of the game, as well as maybe adding a song menu to take away from the constant wall smackings.
As well you could add things to the Flappybird formula that could make it your own/better. Having the bat wince when it crashes as opposed to him keeping the same face, level selection and even character skins. THE WORLD IS YOUR OYSTER!!!...in terms of game design...:P
A few changes would make your rendition stand out more as well as make it more enjoyable.
Good luck! :P