Kerkerkruip is written in Inform 7, which compiles a Glulx story file. Most new players will want to use one of the installers above, but if your OS isn’t supported, or if you already have a Glulx interpreter, you can download the story file directly. If you need an interpreter we recommend Gargoyle, which is available for Windows, Debian/Ubuntu and OS X. (Gargoyle is in fact embedded inside the installers.)
Unfortunately Gargoyle doesn’t support screen readers, so if you use one you’ll need another interpreter. Windows Git has been recommended by some of our screen reader-using players. If you can’t find an interpreter that works, please ask us for help!
Not a download, but still a useful link: the list of commands.