Psychonauts is a terrific game, and plays extremely well in 3D. The game always played well using depth only.
eqzitara created an earlier fix that I expanded upon.
This fix is for all of the problems when convergence was turned up. Skies were the wrong size, and would be too close. You can now use any convergence and depth that you want, including making it look toyified.
All skies, stars, moons, and suns are fixed, in every level.
No known glitches. If you see anything please let me know in the comments.
How to install:
1) Use the Aion profile, like before. The current NVidia Psychonauts profile (for 314.22) is completely unplayable.
2) Extract this Psychonauts.zip into your game directory.
Steam version was used, as:
x86: C:\Program Files\Steam\steamapps\common\psychonauts
x64: C:\Program Files (x86)\Steam\steamapps\common\psychonauts
3) If you have crashes at cut scenes, change the Properties of the exe to compatibility mode for Win95. Yes, Win95. That is the suggested fix from double-fine, and worked for me.
I also left in the debugging presets, on the off chance someone might be interested. You can disable the fixes by using the numeric keypad Period key. Re-enable the fixes with numeric keypad Enter key. This allows you to toggle back and forth and see the fixes live. Lastly, there is a texture finding tool, of numeric keypad Zero key. This highlights any texture that is seen by a modified shader, but not on the fix list. It's trippy.
Update: 5/12/13: managed to upload a broken Zip file, missing Shaderfolder. Fixed.
Special thanks to eqzitara for excellent suggestions.