The Oni demo that was released last month (for PC story and Mac story) contained a tutorial level as well as levels 1 and 4 from the full game. Recently Oni Central discovered that the cover demo on PC Gamer includes level 2 instead of 4, and this level has since been made available separately in this forum post (mirrored on FilePlanet). For the PC, the 17.8 MB file simply needs to be unzipped in your Oni demo folder, while OniRes offers a few tips for installing it on the Mac. The new level will become available once you complete the first level of the original demo. Thanks VoodooExtreme for the tip and Oni Central for all details.