I felt that the 'teaching' didn't need to be so harsh.
Maybe I'm just a softy for the cat, but isn't it kind of missing 'the point' of practice if we have to kill something innocent to prove it? Even once he said he would cut the cat in half, did he really need to? Was it about sticking to his statement?
I could not work with the shoes-on-the-head part of the koan at all, except that maybe he was using the only thing he had to try to symbolically protect himself from the run-away cutting of the monk. :)