Ozmoo Online

Ozmoo Online

Latest news

2022-11-27: Updated to Ozmoo 11.37, fixing an colour issue with 40-column display on C128.

2022-11-26: Updated to Ozmoo 11.36, fixing issues with 80-column display on C128.

2022-11-06: Reorganized page, putting build results, upload form and files below the build form. Fixed bug in processing Blorb files..

2022-10-05: Updated to Ozmoo 11.31, which lets the player choose slower scrolling, key repeats on/off and change save device.

Recent noteworthy updates

  • Added scrollback buffer for all platforms. Can use REU and/or regular RAM.
  • Ozmoo got REU Boost feature, speeding up gameplay by ~10% when using REU.
  • Added a Play link to single-disk games for C64.
  • Added link to Lurking Horror and Sherlock with sound for MEGA65
  • Added A Mind Forever Voyaging and Trinity to the game list.
  • Accept upload of Blorbed Z-code games
  • Accept building games as .d71 disk images for C64 and Plus/4
  • MEGA65 version now supports Z-code files with dynamic memory of any size, and even lightweight Inform 7 games (select XL stack for Inform 7 games!)
  • Fixed bugs: Corrupted saves on MEGA65, Scrollback bug on MEGA65

Ozmoo is a Z-code interpreter for the Commodore 64, 128, Plus/4 and the MEGA65. It was written by Johan Berntsson and Fredrik Ramsberg, and released in 2018 under the GPL 2.0 license, meaning it can be included with games which are given away or sold. Ozmoo supports Z-code versions 3, 4, 5 and 8. You can use this page to build the interpreter and bundle it with a game. There is more information on the project homepage on GitHub.

Ozmoo was designed to be bundled with a game, much in the same way as the original Infocom interpreters. To do this, you run a Ruby script called make.rb which is included in the Ozmoo distribution. It assembles the interpreter, taking into account the Z-code version and the options specified when calling make.rb, adds as much as possible of the Z-code file, compresses the result and stores it as a file on a disk image. It then stores all the parts of the story that the game may need to load during gameplay in raw sectors on the disk.

Ozmoo can be downloaded and used to build games on Windows, Linux and Mac OS X. As an alternative, we have set up this page where you can build games online. It doesn't support all the possibilities which Ozmoo offers, but enough to get started. Options which are currently not supported on this page include user-supplied custom fonts, custom key-mappings, virtual memory preloading optimization and sound effects (sound is only supported for MEGA65, and not at all when building a game in Ozmoo Online).

Z-code files typically have names ending with .dat, .z3, .z4, .z5 or .z8. They can mainly be found in Infocom games (yes, you can grab a .dat file from say Zork 1 for MS-DOS and use it to build a version for C64 with Ozmoo!) and on if-archive. Z-code files produced by Infocom are usually quite fast on Ozmoo. Z-code files produced by Inform 5 or Inform 6 may at least be fast enough to be fun, but it depends on how much processing they do. Z-code files produced by Inform 7 or Dialog are pretty much guaranteed to be horribly slow, unless you're playing on a MEGA65, in which case Dialog and relatively lightweight Inform 7 titles may be enjoyable (Check the XL Stack option when building an Inform 7 game though, or it will likely crash at some point). There is also ZILF, a modern compiler for ZIL, the language Infocom used to write their games. Z-code files produced by ZILF should typically play just fine on Ozmoo.

Build game
Story file:   
Koala loader image:   
Multi-Botticelli loader image:   
Build mode:  
Language / Font:  
(*) Please learn more about Ozmoo and fonts first!
Command history:
Scrollback buffer:  
Inform 7 XL stack:
Colour scheme
Check out different colour combinations here.
Statusline:     (z1-z3 only!)
Input text:     (z1-z4 only!)

Upload Z-code file (.dat .z1 .z2 .z3 .z4 .z5 .z7 .z8), Blorb file (.blorb .blb .zblorb .zlb), Koala Paint multicolour image (.kla) or Multi-Botticelli image (.mbo)

Your files: