Select exhibition mode, then at the team selection screen, repeatedly tap C-Left + C-Right + C-Up + C-Down
Wait for your opponent to hit a pop-fly to the outfield but dont catch it. Instead, pick it up, hold Z, and press C-up to run it in. Then press the following C buttons to throw to bases: RIGHT, UP, LEFT, DOWN, LEFT, UP, DOWN, RIGHT, UP, LEFT, DOWN. You should hear the crowd boo. On the next hit, don't get the ball. Instead, repeatedly hit A or B and your player will fly.
While you're at bat, quickly hit the following buttons: Right, left, down, right, left, up, right, left, down. If done correctly, the batter will explode.
Highlight Exhibition from the main screen, and press all four C buttons together until you hear a bell. You should find two new teams at the Team Select Menu.
When Ken Griffey Jr. is up at bat, pause the game and press Left, Left, Right, Right, Right, Left, Left on the d-pad. Unpause the game and Griffey will point his bat towards the outfield. If you hit the very next pitch it will be a home run.
If you're pitching or batting, press the following buttons on the control PAD (not the stick) to dance: UP, UP, DOWN, LEFT, LEFT, RIGHT, RIGHT, LEFT, LEFT, DOWN, UP, UP
While batting, hold B, and the batting cursor will zoom in on where the ball will be thrown, as soon as it moves, let go of B, and whack a homerun.
To do this, the ball needs to be hit very high, to the point where you see the huge shadow on the field. When you see the huge shadow, run all the way back to the wall and get in alignment with the shadow. Now instead of jumping and trying to rob the homerun just stand there, and when you do this, your player should warp through the wall and catch the ball for an out. And if it's not a homerun, the ball will bounce off the wall right into your hands.
Pass the World Series on All-Star difficulty and you may use the Draft First (you get first pick) and Draft Team (you draft your entire team before any other team gets a pick) when drafting at the beginning of a season.
Place the crosshair anywhere outside the yellow batting circle and hold it there. Then, hold Z and press C-Up, C-Left, or C-Right to look at one of the bases. Now release Z, then release the other button. The crosshair will disappear from the pitching screen. Select and throw any pitch, which will always be a strike or a ball. This is always unhittable.