For a stick game, it's sweet.
It was actually fun for a bit. (although I don't really recall badminton being played indoors so that the birdie can hit the wall and still be counted inbounds, but oh well).
Regarding keyboard controls, I actually used the a s and w keys for movement and the down key for the racket so I can use both hands. As soon as I got adjusted to how it played, the game was easy. Then again, the computer is scripted to make mistakes too quickly.
It actually had an ending to the vs. CPU mode too. (Okay, it's just an newspaper clip, but still).
Was it really hard before? Was it because you initially programmed the computer player to be too good at returning volleys? You should have left that hard mode in game.