For an experienced puzzler such as myself, this game really wasn't difficult at all. The longest I had to think about any level was about 15 seconds, with the exception of the last level which took closer to 30.
That said, the music was nice, the gameplay was solid (though I wouldn't complain if the movement of the puncher was sped up a little), and I couldn't find any bugs at all. So well done on the game design, it's just the puzzle design that could use some more time in the incubator.