DFC2-A494 1 credit instead of 3--player 1
D4C2-A494 2 credits--player 1
D9C2-A494 5 credits--player 1
D5C2-A494 7 credits--player 1 
DBC2-A494 9 credits--player 1
DDC2-A494 No credits--player 1
DFCF-DFF7 1 credit instead of 3--player 2
D4CF-DFF7 2 credits--player 2
D9CF-DFF7 5 credits--player 2
D5CF-DFF7 7 credits--player 2 
DBCF-DFF7 9 credits--player 2
DDCF-DFF7 No credits--player 2
C260-67F7 Infinite credits--both players
7A64-D420 Clock runs faster
ED64-D420 Clock runs slower
ED64-D420 + DF64-D7F0 Clock runs much slower
8269-DF90 Freeze clock--must switch off effects in bonus stage
DF6D-D7BD 1 play per game instead of 3-- both players
D46D-D7BD 2 plays per game--both players
D06D-D7BD 4 plays per game--both players
D96D-D7BD 5 plays per game--both players
D56D-D7BD 7 plays per game--both players
DB6D-D7BD 9 plays per game--both players
C26E-6D2D Infinite plays--both players
6DA6-6D69 No harm from most enemies
C23B-A7F9 + C232-67B1 No harm if swallowed by a monster
D427-6D2D Collect 2 eggs for extra play instead of 50
D927-6D2D Collect 5 eggs for extra play
FD27-6D2D Collect 10 eggs for extra play
F927-6D2D Collect 15 eggs for extra play
4927-6D2D Collect 25 eggs for extra play
5927-6D2D Collect 75 eggs for extra play
BB27-6D2D Collect 99 eggs for extra play
EC6B-DFBE Rex jumps higher
E66B-DFBE Rex jumps much higher
EC8A-D793 Tops jumps higher
E68A-D793 Tops jumps much higher
EC22-DF22 Timmy and Jamie jump higher
E622-DF22 Timmy and Jamie jump much higher