It seems to be level 3 when I get into the cave far enough that the background image changes. I can fly around all I want doing whatever I want as long as I stay high enough up to not have that background. Note that I ran the game as an administrator (Windows 10) and that seems to have solved it.
I tried that but there wasn't even a ThrustMe folder there. Now that I've run as Administrator, the folder is there and logging.txt is there but it's empty. But I've also not had any crashes. :) I will launch without admin and see if I can get it to write there now that the folder and log file exist.