I found the game difficult - but that is only because i lack the ability to judge the timing.
With plenty of practice i could play the game well and it would be be challenging with lots of replay value. :)
Only real issue for me: I found it a a little hard to read the text on the screen - i would love for the game screen to be larger or be able to adjust the screen size myself. (Maybe there is a way and i was just too stupid to figure it out though, apologies if that is the case)