Playing Kevan Davis's Rubicon in 2026

A Rubicon level (level code: zefecod). A 9 crate at the left side of the level must be matched to a 1 crate at the right side of the level. A solution has been built involving adding copies of the 9 crate until an 8 crate emerges, then adding that crate to the 9 crate.

We use Debian 12; this article reflects that.

Basic setup

The Rubicon applet uses two separate .jar files that must be combined to run it normally. (Unless someone who's better at Java than us knows how to run code in two separate .jar files at once.)

  1. Go to https://kevan.org/rubicon/game.html , feel a tang of despair at the fact that "how do I run Java applets" has been lost knowledge for something like a decade now, and also that Jay Is Games has been reduced to an SEO funhouse.
  2. Replace "game.html" in the link with "rubicon.jar" to download the game code.
  3. Replace "rubicon.jar" with "core.jar" to download the Processing framework.
  4. In xarchiver, extract the "processing" folder from core.jar.
  5. In xarchiver, open rubicon.jar, and add the "processing" folder to the archive.
  6. If you did the last step by drag-and-dropping, navigate into the "processing" folder now in rubicon.jar, and manually add the "core" and "xml" folder from the outside "processing" folder to it, because xarchiver doesn't recursively add subdirectories when you drag-and-drop, it's weird.
  7. Install openjdk-17-jre, or whatever version of openjdk-xx-jre is available on your package manager.
  8. java -jar rubicon.jar. "param() only works inside a web browser" will show up in stdout, but you don't need to worry about that.

It's possible that upon trying to open rubicon.jar, it will show as a minimum-size window with no graphics. I don't know why that happens, but we were able to get around it by first launching another Java app that's consistently able to initialize its own display. Download http://rockz.co.uk/preview/plugin/rockz.jar and launch that before rubicon.jar and the issue should be solved (and don't poke around too much on that site unless you want to find out what the creator of Repton thinks about climate change).

Playing user levels

  1. Find the level you want to play. If you know the level code, go to https://kevan.org/rubicon/userlevels/warehouse/xxxxxxx.rub but replace the xxxxxxx with the code. If not, see if it's on the forum archive, or else trawl https://kevan.org/rubicon/userlevels/warehouse/?C=M;O=A and hope you get lucky (as we did when we were looking for a very late level we uploaded).
  2. Download it with "save page as".
  3. Make a copy of it named "level1.rub", open that copy in a text editor, and remove the header at the start of the file so just the level data remains.
  4. Make a backup of rubicon.jar if you want, then open it in xarchiver, navigate to "data", and add the new level1.rub, which will replace the version already in the archive.
  5. Open Rubicon and click "Play Base Levels", which will take you to Level 1, which will be the level you've just inserted.

Extra

https://kevan.org/rubicon/userlevels/warehouse/aaaaaaa.rub contains the source code for Rubicon v1.26. You can use this to confirm some more esoteric element behavior, such as the weird logic behind key doors that makes levels like Bucky's "Flux Panels" (buvuduc) possible.

It is worth noting that we figured out that the "processing" folder can be added to rubicon.jar from observing the structure of https://kevan.org/rubicon/beta/rubicon.jar (which was shared on the forums to demonstrate the changes being made to packer speed).

BACK.