Cheat mode (enter before the others):
Start a new game and pause it. While paused, use Controller 2 and press Triangle, Square, X, Circle, Circle
Computer vs. Computer:
Enter Cheat Mode and press L2. To regain control, re-enter Cheat Mode and press L2 again.
Home Run:
For an automatic home run (if you hit the ball), enter Cheat Mode and press L1, then unpause the game. To revert to normal, re-enter the Cheat Mode code and press L1 again.
Inning Select:
Enter Cheat Mode and press X to bring up a "Let's Go Inning" menu in the upper left-hand corner. To change innings (up to 18), re-enter Cheat Mode and press X.