Bubble Bobble (ZX Spectrum, 1987) JavaScript port -- debug build for testing, 16.10.2026

The ZX Spectrum version of Bubble Bobble (Firebird Software, 1987), ported to JavaScript. This is not emulated software but a faithful reconstruction based on the disassembly of the Z80 machine code, every behaviour measured against the original running in a simulated ZX Spectrum. Both of the tape's games are here: the 128K with Tim Follin's AY music (the default) and the 48K with its beeper (Alt+M switches between them).

This is the debug build, for testing. It is the faithful game with a panel down the right-hand side that jumps to any round, kills the enemies, places power-ups and food, gives EXTEND letters and lives, triggers HURRY UP, and runs the game slower, faster or a frame at a time. Every action works through the game's own routines.

The ZIP holds a single self-contained HTML file and a short README: unzip it and open bubble_bobble_debug.html in Chrome, Edge or Firefox on a desktop computer.

Keys

Keys
Alt+P	pause and resume
Alt+Q	end the game
Alt+M	switch machine, 128K / 48K (remembered)
Alt+Enter	fullscreen (Escape to leave)

At the start each player chooses KEYBOARD (and defines the keys), SINCLAIR, KEMPSTON or CURSOR; the caption under the screen names each player's keys. KEMPSTON reads nothing yet: there is no joystick or gamepad support. The debug panel's shortcuts: Alt+X freeze and run, Alt+C one frame, Alt+N clear the round, Alt+K kill the enemies, Alt+L a life, Alt+I invincible.

Not bugs: the original does these

• Round 30's spring enemies stutter once you have moved, and heavily after HURRY UP. A real Spectrum does the same. (The port's 128K shows it noticeably more often than a real 128K does; that is known.)
• Jumping to round 20, 40 or 60 does not take you to the treasure room. Reaching those rounds by play, without losing a life, does.
• After the blue bottle (power-up 13) nothing is picked up until you lose a life.

Reporting a problem

Please open an issue with the browser and operating system, the machine (128K or 48K: the caption under the screen says which), the round, and what you did and saw. For a sound problem, press F12, run __PORT__.sound.info() in the console and include what it prints.

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Bubble Bobble © 1986 Taito. ZX Spectrum version by Software Creations (code Mike Follin, graphics Andrew R. Threlfall, music Tim Follin), published by Firebird Software in 1987. This port is a reimplementation for study and preservation.