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Play Wonder Boy III - Monster Lair (Japan edition · Japanese · Edition 83655) Online

Wonder Boy III - Monster Lair (set 4, Japan, System 16B) (FD1094 317-0087)

Guide Leo through platform action and shooting stages on a flying mount.

Browser play

Arcade — EmulatorJS controls

Default Player 1 keyboard mapping. Change keys in Controller Settings.

Console button	Keyboard
↑ / ↓ / ← / →	↑ / ↓ / ← / →
RetroPad A / B / X / Y	Z / X / A / S
L / R	Q / E
Insert coin	V
START	Enter

Open Controller Settings to configure your keyboard or gamepad. Touch controls are available on mobile.

How to Play Wonder Boy III - Monster Lair

Quick start

Collect fruit during the on-foot sections and adjust your path when flight begins. Watch the boss’s changes before moving closer.

Controls

Move the character and attack enemies. In shooting sections, steer the flying mount and avoid hits.

Wonder Boy III - Monster Lair — About this game

Leo alternates between platform action and firing from a flying creature. On foot, energy drains over time and fruit restores it. In flight, energy is lost only when taking damage. A boss follows, with colors that indicate its condition.

Cheats

Infinite Credits

1 "开启", 0, 0xFFC8A6, 0x09

Select Starting Stage

1 "1", 0, 0xFFC912, 0x00
2 "2", 0, 0xFFC912, 0x01
3 "3", 0, 0xFFC912, 0x02
4 "4", 0, 0xFFC912, 0x03
5 "5", 0, 0xFFC912, 0x04
6 "6", 0, 0xFFC912, 0x05
7 "7", 0, 0xFFC912, 0x06
8 "8", 0, 0xFFC912, 0x07
9 "9", 0, 0xFFC912, 0x08
10 "10", 0, 0xFFC912, 0x09
11 "11", 0, 0xFFC912, 0x0A
12 "12", 0, 0xFFC912, 0x0B
13 "13", 0, 0xFFC912, 0x0C
14 "14", 0, 0xFFC912, 0x0D

One-hit Boss Kill 1

1 "开启", 0, 0xFFE6D3, 0x01

One-hit Boss Kill 2

1 "开启", 0, 0xFFE8B3, 0x01, 0, 0xFFE893, 0x01, 0, 0xFFE873, 0x01, 0, 0xFFE853, 0x01, 0, 0xFFE833, 0x01, 0, 0xFFE813, 0x01, 0, 0xFFE7F3, 0x01, 0, 0xFFE7D3, 0x01, 0, 0xFFE7B3, 0x01, 0, 0xFFE793, 0x01

One-hit Boss Kill 3

1 "开启", 0, 0xFFE6D3, 0x01

One-hit Boss Kill 4

1 "开启", 0, 0xFFE6D3, 0x01

One-hit Boss Kill 5

1 "开启", 0, 0xFFE6D3, 0x01

One-hit Boss Kill 6

1 "开启", 0, 0xFFE733, 0x01

One-hit Boss Kill 7

1 "开启", 0, 0xFFE765, 0x01

One-hit Boss Kill 8

1 "开启", 0, 0xFFE7F3, 0x01

One-hit Boss Kill 9

1 "开启", 0, 0xFFE793, 0x01

One-hit Boss Kill 10

1 "开启", 0, 0xFFE6F3, 0x01

One-hit Boss Kill 11

1 "开启", 0, 0xFFE893, 0x01

One-hit Boss Kill 12

1 "开启", 0, 0xFFE6F3, 0x01

One-hit Boss Kill 13

1 "开启", 0, 0xFFE6D3, 0x01

One-hit Boss Kill 14 (first)

1 "开启", 0, 0xFFE6F3, 0x01

One-hit Boss Kill 14 (second)

1 "开启", 0, 0xFFE8B3, 0x01

Infinite Lives PL1

1 "开启", 0, 0xFFC099, 0x07

Infinite Energy PL1

1 "开启", 0, 0xFFC088, 0x37

Character Invincibility PL1

1 "开启", 0, 0xFFE510, 0x01, 0, 0xFFC08D, 0x0F

Player verification and sources

Browser play was reviewed before this edition was published in the catalogue. The date below is the catalogue publication date, not the game’s original release date.

Browser test and catalogue publication date: October 20, 2026
Browsers and devices: PC: Chrome, Edge and Firefox. Mobile: Chrome on Android and Safari on iPhone and iPad.
Player engine and core: EmulatorJS 4.3.0-pre · arcade
Tested by: rwEmulator

Sources and editorial basis

rwEmulator reviews edition metadata, release information, game manuals and first-hand browser-play notes. Available manuals are linked below; the editorial policy explains how facts are checked and corrections are handled.

Editorial policy and sources Trust center EmulatorJS player help