This is really fun but a little easy.
My opponent and I would press our keys at pretty much the same time so it was a stalemate most of the time.
I think a little variation and speed increase would add some challenge.
Also, the next letter should appear early if the player presses the key early.
I often found myself waiting for the next letter.
But overall, the game is very clean and has brilliant art!
It also looks a lot more relaxing than it actually is :D