it is pretty easy if you practise for a day!!
i have played the game about a year ago and was about to smash my controller because i thought it was too hard.... year later ( a week ago ) i wanted to get the 1000gamerspoint so i gave it a try, after a HARD START i knew what the cpu does and how they shoot most of the time+ its not that hard!!! i got all star circuit beat easily with all characters!!