Major League Baseball Featuring Ken Griffey Jr. cheats and cheat codes for Nintendo 64

Fireworks
Choose exhibition mode. Go to the stadium selection screen, after
enter "View Stadium" mode by pressing Z. Then, hit R + Z.

Exploding batter
Hit Right, Left, Down, Right, Left, Up, Right, Left, Down buttons
while in the batter's box.

Homerun
Hit Left, Left, Right, Right, Right, Left, Left while in the 
batter's box with Ken Griffey Jr. before the pitcher winds 
up to throw the ball. Ken Griffey Jr. should be point his bat in
the direction where the ball will be hit. After, connect with 
the ball to automatically hit a homerun.

Dancing batter
Hit Up, Up, Down, Left, Left, Right, Right, Left, Left, Down, Up, Up
while in the batter's box.

Dancing pitcher
Hit Up, Up, Down, Left, Left, Right, Right, Left, Left, Down, Up, Up 
while in the batter's box.

Change outfit color:
Go to the team selection mode and choose exhibiton mode, then 
repeatedly press C-Left + C-Right + C-Up + C-Down.

View ending sequence
Choose the exhibition mode, and select the same team as home and 
visitor. Jump to the stadium selection menu and hit C-Left, C-Right,
C-Left, C-Left, C-Right, C-Down, C-Up, Z.

Unlock Nintendo and Angel Studios teams
Highlight the "Exhibition" selection and repeatedly press 
C-Left + C-Right + C-Up + C-Down. After, choose the "All-Star teams" 
option to play with the bonus teams.

Show CPU pitcher status
Hit R, on controller 2 while the CPU is pitching.