When Milon arrives at Castle Garland, the people were being attacked by the Evil Warlord from the north region.

Milon volunteers to fight the Warlord and his demons and to rescue Queen Eliza and the musical instruments for the people of Hudson.

However, the Castle's Magician tells Milon that Queen Eliza has hidden many tools, instruments and money to help him.

The Magician also gives Milon a magic "Bubble" to assist him in finding the places where the helpful items are hidden and where they may be bought.

Although seemingly basic, the only way the bosses can be reached is by finding a host of secrets, some of which require sheer luck or a helpful manual.

When a demon-monster dies, it stays dead and releases a crystal ball and, at times, make Milon's bubbles larger and causes them to fly out further.

Unlike in most platform games of the era, Milon does not "blink" to become briefly invincible when he is attacked by an enemy, which means his energy can be sapped very quickly if he does not move away.

This is offset by the fact that each room in the castle has a "honeycomb" which restores the player's life bar entirely and extends it by one unit.

Each time the player collects a music box and is transported to the minigame, a new elf with a new instrument appears, and the song gets more elaborate.

Milon's Secret Castle was released for the Famicom (Japan) on November 13, 1986[1] and later for the Nintendo Entertainment System (North America) in September 1988.

The NES version was re-released in 2005 as part of a compilation on the Game Boy Advance known as Hudson Best Collection Vol.

[10] Provo criticized the control scheme, saying Milon "runs like his feet are greased, and his jumps are easily interrupted by nearby blocks that are adjacent or directly above him".

[13] In 1996, a Super Famicom sequel to the game was released only in Japan, known as DoReMi Fantasy: Milon no Dokidoki Daibouken.

Milon's Secret Castle was one of the video games based on Manga titled Famicom Rocky from 1985 to 1987 and Nekketsu!