Programmers' screen:
Press A + B + Start at the title screen.

Hint: Better pinch hitters:
When selecting a pinch hitter, choose a player with a last name that starts with a "H" for a better chance of them getting a hit.

Hint: Automatic plays:
Select the ''Watch Game'' option to start a CPU vs. CPU game. Use the controller during the game to start manually controlling the home team. When you need to make a play, stop using the controller and the CPU will assume control of the team.