This may not be all of the possibilities but basically what's relevant to the 100% category:

S1
MUSASHI... DEFEAT STEAM KNIGHT
BEE PLANT (PURPLE)... DEFEAT STEAM KNIGHT
SOLDIER 1 (RED)... DEFEAT STEAM KNIGHT
SOLDIER 2 (BLUE)... DEFEAT STEAM KNIGHT
ROOTRICK... DEFEAT STEAM KNIGHT
STEAM KNIGHT... DEFEAT STEAM KNIGHT

S2
SOLDIER 3 (GREEN)... KILL ONE (SHRINK IS OKAY)
HERB PLANT (GREEN)... KILL ONE (SHRINK IS NOT OKAY)
KILLER MAN EATER... KILL ONE (KINDA GIVEN)
MAGICIAN... KILL ONE (SHRINK IS OKAY)
SLEEPIE (RED SHROOM)... KILL ONE (SHRINK IS OKAY)
SKULLPION... DEFEAT SKULLPION

S3
REGULAR VAMBEE... KILL ONE (GIVEN IN DARK ROOM)
VAMBEE SOLDIER... CHURCH BATTLE
BOWLER... KILL ONE
CURE WORM... KILL ONE
BUBBLES... CHURCH BATTLE
RELIC KEEPER... DEFEAT RELIC KEEPER

S4
PENGUIN... KILL ONE (KINDA GIVEN IN RED EYE ROOM)
HAYA WOLF... KILL ONE WITH LUMINA
SLOW GUY... KILL ONE (KINDA GIVEN IN GREEN EYE ROOM)
STEEL GOLEM... ASSIMILATE ONE
GINGERELLE... GET TO FROST PALACE
FROST DRAGON... DEFEAT FROST DRAGON

S5
GIANT (RED/PURPLE)... KILL ONE
TOADSTOOL (PURPLE SHROOM)... KILL ONE
ED AND BEN... WATER CREST IN WELL
TOPO... STEAMWOOD II
COLONEL CAPRICOLA... DEFEAT FROST DRAGON
QUEEN ANT... DEFEAT QUEEN ANT

S6
SOLDIER 1H (FENCING)... KILL ONE (GRENADE IS FINE)
SOLDIER 2H (GUN)... KILL ONE (GRENADE IS FINE)
SOLDIER 3H (HOMING)... KILL ONE (GRENADE IS FINE)
BIG WALKER... KILL ONE (GRENADE IS FINE)
FLATSKI... DEFEAT TOWER OF DEATH
TOWER OF DEATH... DEFEAT TOWER OF DEATH

SPECIAL
FILLET... ALL BINCHOS
JON & LENO... ALL TREASURE
MOTHER MINKU... DEFEAT MOTHER MINKU
KOJIRO... GIVEN BY FARMER LACTER
DARK LUMINA I... BEAT THE GAME
DARK LUMINA II... LEVEL 28 & ALL L ARMOUR
DARK LUMINA III... ALL TOYS