"LowLevelFatalError" or Startup crash.

[Eddie Riggs]

If you are receiving a "LowLevelFatalError" error message, and you meet the game's minimum hardware requirements, then try launching the game in DX11 mode.

Right click Psychonauts 2 in the steam client and enter the Properties menu.
In the general section, enter the text below in the "Launch options"

-DX11

Also, if the crash occurs in the middle of the game as opposed to the start, and you are above the min-specs, some users have reported that reinstalling the game alleviates the issue. So please also try reinstalling the game if you are blocked by this crash.

There are also reports that certain programs do not like to play nice with UE4. One such program is "Sonic Studios 3" which comes packaged with some ASUS products. Try temporarily uninstalling the program to see if it helps.