Please take note: Because of the way Wario Land uses battery backup 
RAM, this cart will not work on some Game Genie/Game Boy 
combinations. There is nothing hat can be done about this. (One thing that 
sometimes helps is installing fresh batteries or using an adequate 
power supply.)

Enter codes, press Start, go into "clear" pipe on the right side, move 
the bomb to desired pipe, press Down, then go down that pipe as Wario

10B 7D8 F7E Start with 10 lives
25B 7D8 F7E Start with 25 lives
50B 7D8 F7E Start with 50 lives
99B 7D8 F7E Start with 99 lives
00B 7E8 E6E Start as Small Wario
02B 7E8 E6E Start as Bull Wario
03B 7E8 E6E Start as Jet Wario
04B 7E8 E6E Start as Dragon Wario
FAD 63F 4C1 Don't lose current power-up when you get hit or get a new 
power-up (switchable)
10B 7C8 E6A Start with 10 hearts
25B 7C8 E6A Start with 25 hearts
50B 7C8 E6A Start with 50 hearts
99B 7C8 E6A Start with 99 hearts
10B 7B8 E6A Start with 10 coins
25B 7B8 E6A Start with 25 coins
50B 7B8 E6A Start with 50 coins
99B 7B8 E6A Start with 99 coins
01B 7F8 E6A Start on course 26
103 E4F E6E Get 10 hearts for killing an enemy
253 E4F E6E Get 25 hearts for killing an enemy
503 E4F E6E Get 50 hearts for killing an enemy
993 E4F E6E Get 99 hearts for killing an enemy
003 AAB E62 + C96 C0C 4C1 Most enemies and obstacles are invisible