Level Codes: Easy Mode: Enter Code at the Main Menu:

Asteroid Field: WM5DR5H3MCLB
Yokian Moon: KVZQG3Q50LZG
Yolkus: 51867F7MJ5YP
Yokian Palace: MMS-KXBVC4FS
Dungeon: N?+94T1?DJXW
Boss 1 Poutra: 939BSYT41N0Z
Boss 2 King Goobot: BD5VVRDF3GXV
Ending Scene: 3L!VPH26V7$8

Level Codes: Hard Mode: Enter Code at the Main Menu:

Asteroid Belt: 2040YL61TT0T
Yokian Moon: GGP6WCC273-3
Yolkus: 2H?-!L81TT0K
Yokian Palace: +R6H!L91TT0F
Dungeon: 456N$DWBWM?F
Boss 1 Poutra: XZ16F2F8NS$!
Boss 2 King Goobot: GRZB87HNYFR2
Ending Scene: +CLT3LD1TTSF
 

Gameshark Codes

Must Be On [M] 50F69A4E2A2CE340   DB6B1F5625577B14
Infinite Lives 1B55B99A3690E337 
Infinite Health 0881E3B177EF448E 
Invincible 7B18EC999B5EE2C8 
Infinite Fuel 0297EC29113C9598 
Always 100% 2BC03CFBB39953CD 
Inf Shrink Ray/Laser A7ABD8C66A7448DC 
Max Score 2A042FC56B531E47