From Armagetron

ZeroInstall is another one of those cross-distribution application installation systems. It's a lot more sophisticated than autopackage ever was and PortableLinuxApps strives to be, and yet it seems easier to build packages with it. Took maybe half an hour, and it would have been possible to let it work from binary archives we already have; I opted to create a binary tarball regardless for speed and simplicity. This system supports dependencies so we don't need to bundle all our libraries in every package. It automatically checks for updates periodically, developers can attach stability ratings to versions, users can override them. So if there's a bug in one version, everyone can mark it as bugged and until an update is out, the previous version will be used. We know this is going to be useful sooner or later

To use you will have to you need to install something before you can use it. Check out here for instructions: https://0install.net/users.html

Once 0install is installed now you can choose what version you want to use:

Version Feed
Armagetronad Alpha https://0install.armagetronad.org/armagetronad-alpha.xml
Armagetronad Alpha Dedicated https://0install.armagetronad.org/armagetronad-alpha-dedicated.xml
Armagetronad Beta https://0install.armagetronad.org/armagetronad-beta.xml
Armagetronad Beta Dedicated https://0install.armagetronad.org/armagetronad-beta-dedicated.xml
Armagetronad Experimental https://0install.armagetronad.org/armagetronad-experimental.xml
Armagetronad Experimental Dedicated https://0install.armagetronad.org/armagetronad-experimental-dedicated.xml
Armagetronad Stable https://0install.armagetronad.org/armagetronad-stable-dedicated.xml
Armagetronad Stable Dedicated https://0install.armagetronad.org/armagetronad-stable.xml
Sty+Ct https://0install.armagetronad.org/armagetronad-styct.xml
Sty+Ct Dedicated https://0install.armagetronad.org/armagetronad-styct-dedicated.xml

More to come information mainly taken from http://forums3.armagetronad.net/viewtopic.php?f=50&t=21905