Many have asked how you can get all 151 trophies in the Hall of Fame if you don't own the elusive bonus Pokemon Mew.
No problem: Once you open up R-2 Mode, you can rent and use Mew in the Prime Cup (sorry -- you still can't get Mew in Gym Leader Castle and Free Battle). To get the secret R-2 Mode (as well as a brand-new title screen) defeat Mewtwo after you have beaten the Stadium Mode and Gym Leader Castle Mode. You will now see the final credits sequence, which will unlock the harder R-2 Mode and all new battles. You can toggle between R-2 and Regular Mode at the start-up screen by pressing C-Right.