Many years ago when Psychonauts 1 was released I spent a lot of time reverse engineering and documenting its file formats as I made Psychonauts Explorer. Psychonauts stores most of its game data in a .pkg bundle, the audio in .isb bundles and resources for each level in .ppf ‘level pack files’.
In 2011 the game was updated and re-released on Steam and GOG. In the process the format of the level pack files changed. I added support for the other Psychonauts 1 archives to DoubleFine Explorer but I couldn’t figure out the new ppf format. No-one else could either and this meant that for many years no-one could browse the level bundles.
Download it here.