After getting hurt, for a while enemies won't attack and you're invisible by Galoob
Game Genie
6D20-34A8
Don't Fall in Holes by nolberto82
Game Genie
1D84-37A6
Double Toad Speed Except In Vehicles Levels by VisitntX
Raw
7E006D:02
Easy Finish by VisitntX
Game Genie
C220-CF0C
Infinite continues [player 1] by Galoob
Game Genie
C96A-346F
Infinite continues [player 2] by Galoob
Game Genie
C96B-34DF
Infinite Energy by VisitntX
Game Genie
228E-34A0
2280-4DD9
Infinite Energy by VisitntX
Game Genie
C969-3FA0
Infinite Lives by VisitntX
Game Genie
8286-CF01
Infinite Lives by VisitntX
Game Genie
C9CC-C468
Infinite lives when falling by Galoob
Game Genie
8026-CD08
Infinite lives [both players] by Galoob
Game Genie
8986-CF01
Invincibility by VisitntX
Game Genie
2D20-34A8
Invincibility by VisitntX
Game Genie
2DBF-670F
Invincibility by VisitntX
Game Genie
1D8D-1DA6
1D8A-1406
Invincibility by VisitntX
Game Genie
C2B4-3F68
Invincibility against spikes by megaman_exe
Game Genie
1DC1-C40B
Invincibility Except In Vehicles Levels by VisitntX
Raw
7E1092:02
Level Modifier by Helder
Raw
7E002C:0?
Mice don't run in the 6th stage (they just fall and stay quiet) by megaman_exe
Game Genie
C2B8-446C
One Hit Kill by nolberto82
Game Genie
3D87-44A9
DD87-47D9
DD87-4709
CB80-4DD9
EE80-4D09
EE80-4D69
B280-4DA9
P1 Infinite Lives by terpsfan101
Game Genie
CBAF-44D4
69AF-44A4
46AF-47D4
P2 Infinite Lives by terpsfan101
Game Genie
CBA9-4464
69A9-4704
4CA9-4764
Protection against most strength level 1 hits by Galoob
Game Genie
82A7-3FAF
Protection against most strength level 2 hazards by Galoob
Game Genie
8982-CFD1
Slowdown Cpu by VisitntX
Game Genie
DDCB-14D6
DDCF-1D66
DDC8-4D66
Start with 0 continues by Galoob
Game Genie
DD6D-04AD
Start with 10 lives by Galoob
Game Genie
DB6D-0D0D
Start with 2 lives by Galoob
Game Genie
DF6D-0D0D
Start with 5 continues by Galoob
Game Genie
D96D-04AD
Start with 6 lives by Galoob
Game Genie
D96D-0D0D
Start with 9 continues by Galoob
Game Genie
DB6D-04AD
Take less damage from hits by Galoob
Game Genie
8280-4DD9