Aluminum Bats
Go to the "Today's Game Screen" and enter L, R, L, R. Then:
R, A, Z, B, A, L, L for Aluminum Bats.

Colorful Bats
Go to the "Today's Game Screen" and enter L, R, L, R. Then:
R, down, B, A, right for red bats
B, L, B, A, right for blue bats

Crazy Ball
Crazy Ball: Go to the "Today's Game Screen" and enter L, R, L, R. Now do this:
C-Right, A, Z, B, A, L, L.

Crazy Pitch

Go to the "Today's Game Screen" and enter L, R, L, R. Now do this:
C-Right, A, Z, C-Up, R, B for Crazy Pitch.

Credits
Enter the following code at the titles screen to enable a credits option:
R, A, Z, R, C-Right, A, B.

Devil's Thumb Stadium
Go to the "Today's Game Screen" and enter L, R, L, R. Now do this:
To get the Devil's Thumb Stadium, press right (D-Pad), A, C-Up, L, A.

Easy Homeruns
Go to the "Today's Game Screen" and enter L, R, L, R. Now do this:
Press L, A, down (D-Pad), R to always hit a homerun.

Easy Steals
Go to the "Today's Game Screen" and enter L, R, L, R. Then:
C-Left, A, down, (D-Pad) C-Up, Z for easy steals.

Game Speed
Enter L, R, L, R at "Today's Game Screen."
Now enter L, A, Z, R, B, A, L, L for fast games
or up, L, L, B, A, L, L for slow games.

Gravity Options
Enter L, R, L, R at "Today's Game Screen."
Now enter up, R, A, L for low gravity
or: up, down, L, up, R for increased gravity.

Hidden Messages
At the title screen (the one with Piazza's picture), enter:
C-Up, R, B, B for hidden messages.

Psycho Bats
Go to the "Today's Game Screen" and enter L, R, L, R. Then:
Z, B, R, A for Psycho Bats.

Varied Pitches
Go to the "Today's Game Screen" and enter L, R, L, R. Now do this:
C-Right, A, Z, C-Up, R, L for varied pitches.