Colonel Foster and Captain Swann investigate an anomaly at the crater Plotinus on the Moon. I've been unable to confirm Plotinus as an actual crater name.

When the Interceptor shoots down an approaching UFO, it just happens to crash right into crater Plotinus where Foster and Swann are investigating in a moon mobile!

On page 2, panel 5 of the story, it looks like the dialog balloons have been swapped for Colonel Foster and the pilot.

After the strange, reptilian statue speaks and warns Foster and the pilot that the Moon will be destroyed in one Earth cycle (24 hours), Swann says they must get back to their crashed moon mobile and see if the radio is still serviceable to warn Moonbase. But shouldn't they have tried the radio immediately after the crash to let Moonbase know what had happened in the first place?! 

The Ckassk spaceship seen on page 3, panel 9 of the story looks rather like a manta ray. (Manta ray photo from the Adventure in Hawaii website.)

Starting with Part 3 of the story, the aliens are suddenly referred to as the Csassk instead of the Ckassk (though one of the SHADO men does say "Ckassk" again on page 6 of the story).

This story reveals that the alien race called the Ckassk (or Csassk) built a base on Earth's Moon before leaving again about a million years ago.

UNANSWERED QUESTIONS

As they left their base on Earth's Moon in order to return to their homeworld to protect it from invaders, why did the Ckassk feel it necessary to set a booby trap to destroy the Moon in the event another species attempted to inhabit it?