I just remembered that like 10 months ago the thought occurred to me that if you were so inclined you could implement serialisers and deserialisers for Psychonauts' own file formats in Lua and read/write assets from inside the game itself.
This is an absolutely terrible idea with little practical purpose but it's a fun idea. Maybe it would have some limited uses. Like being able to generate some content at runtime. Not 100% what or why but again, very fun thought.
Runtime generated textures/level content based on the current game state or player input, perhaps?
With a lot of blood, sweat and tears you could probably write a level editor inside the game itself which would be funny.
I'm not about to go on a tangent about how I actually did or plan to do this by the way. It's just a thought from months ago that I randomly remembered just now while pondering the architecture of the level editor I've been thinking about.