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Alien Legacy - BUGS FREE

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4X — EXPLORATION / EXPANSION / EXPLOITATION / EXTERMINATION

A new world for humanity.

Take command of an expedition to Beta Caeli aboard the UNS Calypso. Explore planets, build colonies and manage production to keep your crew alive.

Research new technologies, discover alien relics and unravel the mystery of a lost human expedition. Every decision shapes the future of your colonies.

Original game manual ↗

A GAME LIKE NO OTHER

One of the best games I’ve played.

Alien Legacy is still my favorite game, despite its unfixed bugs. My worst memory: a mass driver crashing the game after six hours of play without saving… Then there’s the bug that instantly generates a vehicle, a temptation that’s hard to resist sooner or later in a playthrough.

Who owns the rights to Alien Legacy today? Microsoft? I don’t have a clear answer yet. Creating a mod for this game would be really interesting. For now, I’ve put together a patch to fix a few known bugs. If you have other ideas, share them!

Share an idea

AL-MARS-PATCH

Play Alien Legacy.

Enjoy your game with the experimental AL-MARS project's community fixes. Install the launcher once, then return here and click Play.

The Play button opens PLAY-AL-MARS.exe on your computer. Allow your browser to open AL-MARS when prompted.

AL-MARS · README

Original launcher README, in English.

AL-MARS — ALIEN LEGACY LAUNCHER
EXPERIMENTAL WINDOWS X64 BUILD

QUICK START
1. Extract the AL-MARS folder to a writable location.
2. Open PLAY-AL-MARS.exe.
3. Drop your game ZIP, CD ISO, or extracted game folder into the import
   area. You can also use IMPORT ZIP / ISO or IMPORT FOLDER.
   Recognized English 1.00 copies are updated automatically to official 1.01.
4. Press PLAY and choose DOSBOX-X ON THIS PC, DOSBOX 0.74-3 ON THIS PC,
   or IN YOUR BROWSER.
   Apply patches and your selected exploration settings apply in all modes.
5. In browser mode, press PLAY IN BROWSER on the page, then click the
   game screen to use the mouse and keyboard.
6. To bring existing saved games, use SAVES FROM ZIP or SAVES FROM FOLDER
   in the separate IMPORT SAVED GAMES area. A folder or ZIP can also be
   dropped into that area. Import the game first, then load the imported
   saves through the game's Load Game menu.

Alternatively, place your game ZIP or CD ISO directly in GAME, or place
an already extracted game in GAME\INSTALLED, then press PLAY. The launcher
prepares the game on the first launch. Game files are installed in
GAME\INSTALLED; the ISO remains in GAME. Imported ZIP files from GAME
are moved to GAME\INSTALLED\ARCHIVES.

FOLDERS
PLAY-AL-MARS.exe English launcher. No About or Licenses button.
BUGS.TXT         Included corrections and their evidence.
DOSBOX           Bundled official DOSBox-X, preconfigured by PLAY-AL-MARS.exe.
DOSBOX074        Optional official DOSBox 0.74-3 runtime and its SDL libraries.
BROWSER          Bundled js-dos emulator and browser player.
GAME             Game ZIP and CD ISO, when required.
GAME\INSTALLED   Automatically extracted game files and settings.
GAME\INSTALLED\SAVES
                 Shared saves for DOSBox and browser sessions.
GAME\INSTALLED\UPDATES
                 Original 1.00 executable and official update report.
LICENSES         Component notices, official update README, and source details.

The downloadable package includes Sierra's official updater and its delta,
embedded in PLAY-AL-MARS.exe. It contains no complete game, CD images, or saves.
Supply your own game. When imported, files are named
in uppercase. Existing saves and settings are preserved. A conflicting
installation is refused rather than replaced. Use a separate AL-MARS
folder if you want to keep both the floppy and CD editions.

SUPPORTED GAME COPIES
- Recognized original English floppy 1.00: automatically updated to 1.01.
- Original English floppy 1.01.
- Original English CD 1.10.
- CD 1.10 with our earlier message-only correction already applied.
Other executable variants are unsupported.

AUTOMATIC OFFICIAL SIERRA UPDATE
PLAY-AL-MARS.exe embeds the unmodified PATCH.EXE and PATCH.RTP from Sierra's
Alien Legacy 1.01 Install Utilities disk. No download is required.
When importing a recognized English 1.00 folder or ZIP, or preparing an
existing 1.00 installation, the launcher runs this updater in bundled
DOSBox-X on an isolated executable copy before applying AL-MARS fixes.
The resulting executable must match the exact official 1.01 fingerprint.
Original 1.00 files are preserved under GAME\INSTALLED\UPDATES; imported
source folders and archives stay unchanged. Existing saves are preserved.
Version 1.01 and CD 1.10 skip this step. A failed conversion stops preparation.
The original Sierra instructions are in LICENSES\SIERRA101-README.TXT.

DOWNLOAD SOURCES CHECKED ON 11 OCTOBER 2026
MyAbandonware:
  https://www.myabandonware.com/game/alien-legacy-21h
- Alien-Legacy_DOS_EN.zip (10 MB): recognized English floppy 1.01.
- Alien-Legacy_DOS_EN_ISO-Version.zip (174 MB): recognized English CD 1.10.
Import either ZIP directly. Keep the full ISO archive for the CD edition.

Abandonware France:
  https://www.abandonware-france.org/ltf_abandon/ltf_jeu.php?id=314
- jeu-00314-alien_legacy-pcdos.7z contains recognized version 1.00. Extract
  the 7z and use IMPORT FOLDER. AL-MARS applies the official 1.01 update
  automatically, then prepares its own corrections.
- The automatic setup EXE is not an AL-MARS import format. Import the game
  folder after installation and ensure its executable is a recognized edition.
Direct imports accept ZIP, ISO and extracted folders; 7z files and setup
EXEs are not accepted. Extract 7z files before importing their game folder.
Compatibility is determined by the executable's exact fingerprint, so a site
offering a different or modified copy does not automatically make it supported.

For the CD edition, the ISO stays intact in GAME and is mounted
automatically as the CD-ROM. The installed game runs from
GAME\INSTALLED. A ZIP containing the ISO also works. A complete
extracted CD tree is kept inside INSTALLED and used through a virtual
CD-ROM mount. The small installed 1.10 game folder
alone is not a complete CD copy: it still requires the ISO/media files.
The launcher checks this and explains what is missing.

APPLY PATCHES
Apply patches is checked by default. Uncheck it to play with the original
game behavior for comparison in either native engine or the browser.
All AL-MARS game corrections, both exploration options and automatic
Mass Driver save repair are then disabled. Imported save bytes remain
unchanged, and REPAIR SAVES is unavailable in the launcher window.
Automatic coordinate notes also require Apply patches.
Your choices are stored in OPTIONS.INI and take effect on the next launch.
The official Sierra update from recognized 1.00 to 1.01 still runs during
game import/preparation. It is separate from the AL-MARS corrections.
Use --apply-patches or --no-patches to override the choice for one launch.

AUTOMATIC CORRECTIONS
With Apply patches checked, these corrections run for English 1.01 and CD 1.10.
- Message queue: fixes where the last message is stored when the queue
  is full, preventing writes outside its intended slot.
- Production timer: preserves the remaining production time when
  activity resumes instead of restarting its countdown.
- Mass Driver: uses the installation's cycle time for every destination
  and avoids treating destination numbers as manufactured products
  when calculating costs, preventing the affected crashes and stalled
  deliveries. Bad counters already stored in recognized saves are also
  reset automatically to the installed cycle, with original backups.
- Division guards: protects the affected cost calculations and cost
  display from division by zero.
- Vehicle transit: changing an in-flight ship's mission to Probe with
  the same destination keeps it in transit. The game recalculates the
  route from its current position and uses its normal travel time,
  fuel consumption and arrival routines.
- Exploration forward input: holding the mouse forward control and the
  forward arrow key no longer adds their independent movement commands.
  The active forward key takes priority; either control alone keeps its
  original cadence. Changing from the held mouse control to the key adds
  no extra initial step. This correction is automatic in both play modes.
- Habitat dismantling: refuses dismantling an occupied habitat when the
  other habitats have insufficient room for its residents. Evacuate them
  or provide room first. Empty habitats may still be dismantled.
  This is a preventive guard for the reported human-mine scenario; the
  repeated-pickup duplication itself has not been reproduced locally.

LAUNCHER CORRECTIONS
- Browser: includes the added routines in the executable's declared
  loaded code size. The browser file copy and native memory corrections
  produce the same loaded image; the original AL.EXE stays unchanged.
- DOSBox: applies verified byte arrays directly to the child emulator's
  game RAM. All instruction bytes are read back; a mismatch stops the
  session instead of continuing with a partial patch. No debugger server
  or DEBUGBOX session is needed for normal gameplay.

OPTIONAL EXPLORATION SETTINGS
The 'Remove the extra day when exploring a surface sector' setting in
PLAY-AL-MARS.exe is checked by default: it removes the artificial day added by
the surface-sector selector. Uncheck it to restore the original behavior.
The choice is saved in OPTIONS.INI and applies in DOSBox and the browser
on the next launch. Previously saved choices are respected.
Normal simulation turns and ship travel/probe calls retain their behavior.
Exploration fuel, cargo, science and discoveries retain their behavior.
The omitted call also no longer clears the clock's partial-turn counter.

Command-line override for one launch:
  PLAY-AL-MARS.exe --exploration-no-day-cost
  PLAY-AL-MARS.exe --browser --exploration-no-day-cost
Use --exploration-day-cost to restore original behavior for one launch.

'WASD during exploration' is also checked by default.
During exploration, W/A/D supply the Up/Left/Right movement keys.
This applies in both native engines and the browser. The letters retain
their original behavior outside exploration; the normal arrow keys remain
available. S keeps its original behavior, and Alt+S still saves the game.
Uncheck the option to restore the original exploration keys.
The choice is saved independently in OPTIONS.INI as exploration-wasd.
Use --exploration-wasd or --original-exploration-keys to override it for
one launch. Both exploration options are inactive while Apply patches is off.

KNOWN BUGS AND PATCH COVERAGE
Press KNOWN BUGS / PATCH COVERAGE to view the corrections included in
AL-MARS. Select a row for details and evidence. The list has no filter
menu and contains only included corrections. BUGS.TXT supplies the same list.

The inventory distinguishes automatic corrections, the optional exploration
correction, and the preventive habitat guard. Previously corrupted saves
and the root cause of the reported colonist duplication remain open.
The simultaneous mouse/keyboard forward-input bug is reproduced and
corrected in isolated original input-loop tests for both editions.
Removing the extra day per sector remains a separate optional correction.
The new options and guard are tested against isolated instructions in both
editions; a live exploration/dismantling campaign remains to validate.
Recognized version 1.00 is updated automatically. The inventory is
not exhaustive and the patch is not a full-campaign stability guarantee.

IMPORTING SAVED GAMES
SAVES FROM FOLDER searches subfolders. SAVES FROM ZIP accepts .SAV files
at the root or in nested folders, including a backup of the whole game.
Only .SAV files are copied into GAME\INSTALLED\SAVES, shared by both modes.
Original source files are preserved. With Apply patches checked, eligible
Mass Driver counters are repaired after import, with complete original
copies in SAVES\BACKUP. With it unchecked, incoming saves keep their exact
bytes and only identical raw copies are skipped.
Identical content is skipped, including when repeating an import.
Conflicting names and names outside the supported DOS naming convention
receive a free IM000001-style name. Both differing saves are retained.

The importer checks the recognized stock save header and file size. It
rejects empty, truncated, unknown-format and oversized files, unsafe ZIP
paths, and symbolic links. The full selection is staged and validated
before copying any save. These checks cannot certify all internal state.
CD saves are refused for the floppy edition; floppy saves are accepted
for CD 1.10, as documented by Sierra. No format conversion is performed.
This compatibility guard applies to the importer. The game's own Load
Game routine is unchanged, and saves with other corrupted internal state
are not reconstructed.

MASS DRIVER SAVE REPAIR
With Apply patches checked, recognized floppy and CD saves are checked
automatically after save import and before starting either DOSBox or the
browser. REPAIR SAVES runs the same check immediately without launching
the game. Unchecking Apply patches disables both automatic checks and
the launcher window's REPAIR SAVES button.
Only Mass Drivers in the operating phase and online are considered.
Zero counters and counters above the installation's normal cycle are
reset to the cycle from INST.DAT (6 turns in the original data).
Valid counters, offline installations, construction, assignment delay,
upgrade and dismantling phases, and inactive worlds remain unchanged.
Both save layouts cover all 50 world records.

Before each changed file is replaced, its complete original is saved in
SAVES\BACKUP\MASSDRIVER-<timestamp>-<unique-id>\<save-name>.SAV.
The replacement is atomic. If backup or replacement fails, that save
is skipped and the launcher reports the problem. Unknown, truncated,
incompatible or oversized saves are left untouched.
Repairing again adds no backup when no counters need changing.
This targeted repair does not reconstruct other corrupted game state.

Command-line import (without starting an emulator):
  PLAY-AL-MARS.exe --import-saves "C:\MY-SAVES"
  PLAY-AL-MARS.exe --import-saves "C:\BACKUPS\SAVES.ZIP"
  PLAY-AL-MARS.exe --repair-saves
Use --root "C:\AL-MARS" to target a different launcher installation.

PLAYING
Press PLAY to choose DOSBox-X, DOSBox 0.74-3, or the browser player.
Both native engines apply corrections only in emulated memory. They run
your original AL.EXE directly and create no corrected executable file.
The launcher recognizes the emulator RAM and all game patch signatures,
briefly pauses only its own emulator threads, applies and verifies the
corrections, then resumes and releases its memory-control handles.
Unknown or ambiguous images are refused. Browser mode
verifies the same corrections in a temporary game bundle. The original
installed AL.EXE and CD ISO are preserved, and the game's displayed
version number is retained.

Both modes use GAME\INSTALLED\SAVES.
In DOSBox mode, the game uses this folder directly.
Save manually in the game. Quit the game to return to the launcher.
Alt+Enter toggles fullscreen. Ctrl+F9 closes DOSBox-X immediately.
Fullscreen preserves the original 4:3 display shape, with black borders
where the monitor shape differs. The browser centers the largest fitting
4:3 image; native DOSBox uses desktop fullscreen with aspect correction.
DOSBox 0.74-3 starts in an 800x600 window; Alt+Enter switches to fullscreen.
All modes emulate a 486 with the normal CPU core and start at 23000
fixed CPU cycles to leave time for audio.
On this PC, Ctrl+F11 lowers CPU cycles by 1000 and Ctrl+F12 raises them by
1000 in either native engine. Lower cycles can help when sound and movement
stutter; each new launch starts at 23000 again.
DOSBox-X uses cputype=486; the classic engine uses its supported 486_slow.
Native audio uses a 44100 Hz mixer and OPL rate, 2048-sample blocks,
and a 50 ms prebuffer. The browser uses its separate Web Audio buffer.

In browser mode, save manually with Alt+S.
Use the normal left and right mouse buttons in the game: for example,
left adds vehicle cargo and right removes it. Chrome may use Escape to
release mouse capture or leave fullscreen. Press Escape again for the game,
or click the page's ESC button. In fullscreen, Chrome's supported keyboard
capture sends Escape to the game; hold Escape for two seconds to exit.
The exploration WASD option applies here too, without remapping letters
in the game's other screens.
Saved files are copied to
GAME\INSTALLED\SAVES automatically every 15 seconds and when you click
RESTART or QUIT. This does not save your current progress for you.
QUIT stops the simulation, clears the screen, and enables PLAY IN BROWSER
again. The next start includes the latest saved files from this PC.
While running, PLAY IN BROWSER becomes RESTART. It can restart the game
even after the game's own Quit returns to the DOS prompt. Restart copies
the saved files before stopping the old simulation and starting a new one.
If that copy fails, the old session remains available.
SLOWER and FASTER adjust emulation in 1000-cycle steps through the emulator's
CPU controls. In native DOSBox, use Ctrl+F11 to slow down or Ctrl+F12 to speed up.
The page displays the actual CPU cycle setting. A new game start
returns to 23000 cycles; lowering it can help when sound and movement stutter.
Keep PLAY-AL-MARS.exe open while using the browser page. When you are finished,
close the browser page and the launcher. Closing the launcher stops its
browser session without waiting for the idle timeout.
Previous browser saves for the installed edition are moved into the
shared folder automatically. Different saves with the same filename
are both preserved; the migrated copy receives a BR000001-style name.
Do not load CD saves in the floppy edition.

RUNTIME
DOSBox-X is the unmodified official 2026.10.01 MinGW64 SDL2 build. This
build omits the heavy per-instruction debugger instrumentation present
in the previous Visual Studio build. Normal gameplay starts neither
DEBUGBOX nor the MCP debugger server. Video uses OpenGL without a software
scaler, while audio keeps the explicit buffer settings described above.
These changes reduce avoidable overhead; audio quality still depends on
the host keeping up with the selected emulation speed.
DOSBox 0.74-3 is also bundled as an optional privately extracted runtime.
No system installation is needed. Both official emulator binaries stay
unchanged, and no modified game executable is distributed or created by
native gameplay. To select the classic engine from the command line:
  PLAY-AL-MARS.exe --dosbox-074
PLAY-AL-MARS.exe requires Windows x64 and the .NET
Framework 4.x runtime supplied with current Windows installations.
Browser mode uses the bundled js-dos emulators 8.5.2 WebAssembly build
without debugger instrumentation, and a local page in your default browser.
It needs no Python installation,
external emulator service, or internet connection. The CD files are
extracted from your own ISO into a temporary bundle; the ISO stays intact.

SOURCE AND LICENSE FILES
See LICENSES\SOURCES.TXT and LICENSES\THIRD-PARTY-NOTICES.TXT.
The complete corresponding DOSBox-X source is supplied separately as
AL-MARS-DOSBOX-SOURCES.ZIP. Keep it available alongside the binary
package when redistributing the emulator. The classic engine's matching
source is in AL-MARS-DOSBOX074-SOURCES.ZIP and should accompany its binary.
The launcher is
distributed at https://labonte.id.

AUTOMATIC COORDINATE NOTES (NATIVE DOSBOX)
The launcher panel "LAST COORDINATES READ" keeps the eight most recent
messages containing literal sectors from the message group opened with F1.
It shows sectors such as E-7, F-29 and I-33 together with the original text.
The message group is read as a whole, including lines requiring scrolling.
Messages without coordinates do not erase earlier notes. Rereading a message
moves its note to the top without duplicating it. Worlds mentioned in the
text are listed; sectors are never assigned to a guessed planet.
Notes apply to the current session and reset on the next launch. They are
not attached to individual saves. A text copy remains in the session log
folder as COORDINATES.TXT. Browser and diagnostic modes do not capture notes.

TROUBLESHOOTING
Put AL-MARS outside protected Windows folders. If the game path cannot
be represented by a Windows short path, use a simple path such as
C:\AL-MARS. Only open one launcher per AL-MARS folder at a time.
Native session logs are in %TEMP%\AL-MARS\<session>\PLAY.LOG and DOSBOX.LOG.
Browser session logs are in that session folder's BROWSER.LOG.
No internet connection is needed to import or play your game.

Publication ·

Alien Legacy - Bugs free

Experimental version with the following corrections : • Stuck Mass Driver deliveries • Production finishes too quickly after resuming • Incorrect costs and Mass Driver crashes • Division by zero • Teleportation after changing missions • Already invalid Mass Driver counters in saved games • Double speed when using the mouse and arrow key together • Artificial day added for each explored sector • Dismantling an occupied habitat without room to relocate its residents • Full message queue • Importing incompatible CD saved games into the floppy disk edition

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