Why any of this exists

How the work was done

1. Pull the files off the floppy images, which are ordinary FAT12.
2. Unpack the EXEPACK-compressed executable, and check that the unpack lands on both bounds.
3. Decode the data files until each comes out at exactly the size its format implies, with no remainder to explain away.
4. Disassemble, and read the handlers one at a time.
5. Write the rules down with the address each came from.
6. Port them, with a test for each rule so that a correction has somewhere to land.

Step four produced nearly all the findings. Step six caught the mistakes in step five.

The standard of evidence

The working notes keep three labels deliberately apart:

• Confirmed - proven from the shipped data or the code, with the proof stated.
• Inferred - the only reading consistent with the data, but not directly proven.
• Unknown - not identified, and listed rather than guessed at.

Much of this project's history is inferences that looked like confirmations. An early cell table was built by reasoning about what each cave must contain to be finishable at all. The reasoning was careful, and several of its conclusions were wrong, because a census only narrows the answer once you know what the bytes mean. The withdrawn arguments stay in the working notes, since the way a plausible inference fails is usually worth reading.

What is deliberately not here

The original disk images and executable are not offered here, and nothing on the site links to anywhere that offers them.

What the builds carry

Both playable builds have been served at /play/ since 22nd September 2026. Neither runs without the original forty cave layouts and their quota and time tables, so both deliver them, and that is copied content.

The faithful build also delivers the original sprite sheets, title screens, cartoons and 1987 music, in the form it needs to play them. For the five hidden worlds it uses Aleksi Sahala's reconstructed tiles and select-screen portraits, unchanged and credited to him.

VIP, the enhanced build, uses less of the original. Its sprites and cartoons were generated with the original's own as reference images, and its five hidden worlds from Sahala's drawings, so those are derived from his work. Its title art was generated from a description, and its music is a remix based on the 1987 theme by Nick Scarim. None of that establishes that the build is cleared for publication, and none of it covers the caves.

The research, and permission

The written research describes how the game works. Copyright in a program does not protect its functionality or its file formats as such, and the description is published on that basis. Reproducing code, artwork, music or game content, the cave data both builds deliver included, is a separate question, and publishing the analysis is not treated here as settling any of it.

No permission has been obtained. A request was sent to BBG Entertainment GmbH on 16th September 2026 and has not yet been answered. If permission is granted, this page will say so. If it is refused, or the rights holder asks, the builds come down and this page will say that too.

The code, since people ask

The engine, the format readers, the tools and the format documentation were written for this project, and they are public at github.com/dbhq-uk/rockford-engine, under the MIT licence. That repository holds none of the original game and none of this project's art or audio: it is exported from a private one that keeps the game data the tests run against, and every export is checked for anything that must stay private before it goes out. Without the game, the tests that need it skip.

Whose is what

Rockford: The Arcade Game is copyright First Star Software, Inc. BBG Entertainment GmbH acquired the Boulder Dash intellectual property from First Star in 2017 and the First Star name in 2018, and holds the Rockford and Boulder Dash trade marks. This site is unofficial: it is not affiliated with or endorsed by either company, carries no advertising and sells nothing.

The game began in 1987 as an arcade game on Arcadia Systems' Amiga-based hardware. The MS-DOS version, adapted from the Amiga version and published by Mastertronic, carries these credits in its executable:

• MS-DOS version by Synergistic Software, programmed by John Conley
• adapted from the Amiga version by Fernando Herrera and Tony Manso, with assistance from Todd Weiss
• graphics by David Schroeder, Walter Meyers and David Johnson
• music by Nick Scarim
• game puzzles by Fernando Herrera and Peter Liepa
• based on Boulder Dash, by Peter Liepa with Chris Gray

Corrections

Corrections are welcome. Several of the most useful findings here exist because an earlier confident statement turned out to be wrong.

If you hold rights in anything described here and want it changed or removed, the same address reaches me and I will act on it. The process is under takedown.

dan@dbhq.uk