Lives on the top floor of the Pantheon of Sci-Fi. Set the stage for Sci-Fi. Star Trek and many more borrowed much from Forbidden Planet.
A sequel should be made where the Krell still exist without physical bodies within the enormous Krell machine, 8000 levels, 400 shafts, 20 by 20 miles, going into the very core of Altair IV.
I have a script ready.