Museum Button!

Once you beat the game , go to the last level called the Museum. Go into one of the exibits , walk around, play around, then when you think you are ready to take on a challange than walk over to the desk and wait YOU HAVE TO BE PREPARED, but walk over to the desk and hold x on the red button and all the exibits from every room will come and attack you:

easy- beat it

medium- beat it

hard-beat it after 10 tries

(this get harder and harder lol but if you think you can take it go try it)