The Wonder Boy series has many secrets and its lore is deeply interconnected, so we picked as many references and Easter eggs as possible to keep fans informed! Do note that this includes MAJOR SPOILERS, so if you'd like to discover them yourself, this page should be heavily avoided.
The villain laughing in the spaceship at the end of the game is Biomeka from Monster World 3.
The final boss of Monster Lair is "Fake Book", an alien taking shape of the same hero the protagonists were inspired by.
One of the bosses makes a return from Wonder Boy in Monster Land.
The introductory of the game is a simplified version of the final stage in Monster Land.
NPCs from Monster World 3 replace some shopkeepers in the Game Gear version.
WE5T ONE is a password that unlocks Hu-Man with max hearts, inventory and gold.
To use the Tasmanian Sword, jump and press up!
To swap from Hu-Man to Hu-Girl, enter a transformation room as Hawk-Man and hold up, jump and attack.
The floating temple in Wonder Boy 3: Monster Lair is Poseidon's Temple in Monster World 3.
The music that plays in the spaceship in the final act of the game debuted in Wonder Boy 3: Monster Lair.
The Stone Axe used to build the Legendary Sword is the same one Boy/-Tom-Tom used in his original adventure.
The intro area of Monster World 3 is a recreation of the first screen in Monster Land.
The big fish seen in Poseidon's Temple is a smaller version of the first boss in Monster Lair.
Princess Purapril in this game is a descendant of the one in Monster Lair.
The first area in the game's music is an arrangement of the ending theme of Monster Land.
The Maugham Desert is a re-imagining of the Mam Desert in Monster Land.
The Pygmy Transformation room and transformation sequence is a direct reference to Dragon's Trap.
One of the boss themes is a recreation of the boss theme from Monster Land.
The Myconid boss is a returning foe from Monster Land.
The entrance to the Lilypad Dungeon has bricks that spell "Westone" upside-down.
The Nightmare Castle plays a remixed version of the Last Dungeon from Monster Land.
The Ice Castle has miniature Snow Congs from Monster Land.
The Charmstone is a reference to the stones in The Dragon's Trap.
The Pyramid theme is believed to be inspired by the dungeon theme in Dragon Buster.
The Sphinx from Monster Land makes a return and gets a redesign.
The Prince of Darkworld is the descendant of Drancon, the antagonist of the first Wonder Boy title.
The labyrinth puzzle from Monster Land makes a return in the Nightmare Castle.
There is a hidden merchant in a wall in Purapril City that sells extra magic.
Shion is mentioned in one of the library books in Rapadagna Palace.
Warera (or Fear Incarnate) is Biomeka from Monster World 3.
The four spirits are Shion's companions from Monster World 3.
"Eleanora's Magickipedia" is a book that can be found in Rapadagna Palace.
In the "Cradle of Pepelogoo" song, the theme of Purapril City (Monster World 3) is in the medley.
A painting of the title screen for Monster World 3 can be seen in the remake's palace.
A painting of Princess Purapril and Leo can be seen in the remake's palace.
One of the NPCs remembers his line late in the game, that being "Welcome to Monster World!".
The Sphinx from Monster Land makes a return and gets a redesign.
Asha's parents make an appearance at Rapadagna in the final chapter of the remake.
The Debug Merchant makes an appearance in both games.
The music option in the remake is unlocked via the Sound Test code from the original that could be entered on the title screen (Up, Down, Up, Down, Left, Left, Right, Right ).
Purapril XIII is a descendant of the previous Puraprils from Monster Lair and Monster World 3.
To reach find the Debut Merchant, the player must reach Rapadagna without talking to the Sage of Save. However, in the remake, to reach the merchant, don't save in general.
Unlike the original game, the remake requires you to beat it once to obtain the Miracle Bracelet from the Debug Merchant.
Some treasure chests are found in various palm trees in Rapadagna City. This happens in both the original and remake!
Zeke makes a reference to Double Dragon in Monster Boy and the Cursed Kingdom.
A portrait of the Prince of Darkworld is seen in the Haunted Manor.
The theme of Skullrock Beach is an arrangement of the beach theme from Dragon's Trap.
Previous heroes are on the stained glass of Lupia's chapel. Book (Tom-Tom) is here twice to represent the original Wonder Boy title and its sequel.
Shion and the mermaid appear as statues in the Skies of Aeria.
One of the ice monsters (Yeti) in Wonder Boy in Monster World is seen in a flask at the Haunted Manor.
The intro area is yet another recreation of the opening screen in Monster Land.
Eleanora makes an appearance as a puzzle element via a small statue holding a mirror to reflect light. She also makes an appearance as a statue holding a bowl in the chapel.
The Masquerade Carp boss is a returning foe from Wonder Boy 3: Monster Lair.
The labyrinth puzzle from Monster Land/Dragon's Trap makes a return in the sewers.
A Painting of Mouse-Man is seen in a sunken ship.
The castle from the title screen of Wonder Boy 3: The Dragon's Trap is seen through the observatory telescope. When the player waits long enough, a constellation of Book will show up!
A skeleton appears in the poison swamp that is believed to be one of the NPCs in Monster World 4.
Poseidon makes an appearance as a background element in the Pirate Shore.
The Sphinx quiz makes a return in the Lost Temples.
Jin is cursed into an animal form after defeating the first boss of the game similar to Dragon's Trap.
When descending into The Volcano, images of characters and items from the series can be seen.
The Prince Boots are a direct reference to the ones worn by the Prince of Darkworld from Monster World 3.
Monster Boy is the first game in the series that didn't use the Legendary gear.
The Salamander Cross, Shion's Ocarina and Tom-Tom's Axe are the three legendary artifacts.
Asha's Pepelogoo makes a return and is on the lookout for her (The green-haired girl) throughout the duration of the game.
The Myconid (King Mushroom) boss makes a return from Monster Land and Monster World 3.
The Myconid makes a return in the Crystal Caves, but is frozen in ice.
The Piranha-Man form has a statue in the background during the Ancient Frog boss battle.
Monster Boy is the first game to drop the Purapril bloodline.
Voldrake bears a very close resemblance to the Tyrant Dragon in Monster World 3.
The mini boss theme is a returning song from Monster World 3.
The ghost enemies make a return from Monster World 3.
Twirling a spear is a returning ability from Monster World 3.
The piano song that plays in the Haunted Manor is from Monster Land.
The theme that plays in the tower to Aeria is an elevator arrangement of the stage theme in Wonder Boy (1986).
The themes that in the Castle of Lupia are arrangements of "Mind of Hero" and the "Lair" from Dragons' Trap.
The theme that plays in the Dark Realm is an arrangement of "The Last Dungeon" from Monster Land.
The area that is unlocked within the well has a secret fight with the Meka Dragon.
Banjo Ollie is a cameo NPC that has you collect music sheets scattered throughout the world.
The seagull enemies return from Monster Lair.
The truffle room music is an arrangement of the village theme in Monster World 3 after Alsedo is saved.
Sonia and Alsedo make an appearance in the Ocarina segment of the game.
A painting of Alsedo can be seen in Foximus' house.
The treasure chest jingle is from Dragon's Trap. However, in early versions of the game, a jingle from Monster World 4 was used when opening chests.
Asha is seen in the 100% ending, confirming she is alive and part of Monster Boy's timeline.
The spirits of past heroes make a return as key figures during Jin's journey. However, Book (Tom-Tom) is there twice solely to represent the legendary relics needed to continue the story as stated by the game's director.
