First, pay a visit to the "Options" menu, then enter the "Walk Through Walls" code to enable the second controller. Exit the code screen, put the curser on START, hold down C and press the START button. You will get a stage select menu. Set the "Player Controls" to Grant and then set the "Level" to Raptor Visitor Center 4. Instead of fighting Grant as the Raptor, you will fight Grant as Grant. Just don't walk into the other Grant, because the screen will go crazy.