Disclaimer: I am a masochistic Flappy Bird veteran.
Creative take on the game, and very well polished. I think the physics and collision detection could be more challenging, and the maximum distance between pipes for Arcade should be shorter: Arcade's occasional long distances introduce random periods of button mashing that don't feel fair. My high scores for Arcade and Classic were respectively (a well-earned) 82 and (an easy) 350+, which I think illustrate this point. I say 350+ because at that point, the game starts slowing down, which makes me wonder if you're deleting off-screen pipes?
Also, as a side effect of this game, M and W are now my least favorite letters of the alphabet :)