Boomerang Kid

TAOGPTLA Start with 6 lives
SZOGXVVK Infinite lives

Linus Spacehead

PEKGGLLE Start with 9 lives
AZKKPNAP Increase oxygen
AEULZIPA Never lose oxygen
SXEGLYVG Never lose life in the water
SZXIILVG Never lose life in the land

Super Robin Hood

PAVGILLA Start with 1 life
TAVGILLA Start with 6 lives
PAVGILLE Start with 9 lives
SXNKZIVG Infinite lives
AVONISPG Become invincible
PAEGLTLE 9 energy hearts--you may lose some of the hearts you have when you
pick up new ones

Treasure Island Dizzy

With the first code you will start in the island in the sky, so just
keep walking left and you will arrive at the original starting point
PEXSZYAA Invincible Dizzy
OZNTKASX Walk backwards
PEUSYYAA Start with snorkel
PEUSYYAA + PEKNIZZP Start with axe
PEUSYYAA + ZEKNIZZP Start with dynamite
PEUSYYAA + IEKNIZZP Start with heavy weight