Drake is excellent doing Science Fiction. Meh at fantasy. This story's blend would be tough to do by a master of both.
My basic problem with this story is godlike power being challenged and channeled by machine guns. I have the same problem with movies that have humans fighting angels and demons with guns.
Guns and bombs work fine against spears and rocks, so so against missiles and lasers... But against world eating, world making, giant whatises?
Of course these "gods" don't even have security systems or the idea of cameras. Basically if you turn modern humans into Norse gods you need to explain why they lack modern thoughts and act like super primitives. If going for a "space Edda" I'd've just inserted "space gods" (non human?) instead.
The reason it's 3* instead of lower: The individual sections are ok as light adventure. But it's a mess as a whole.