In broad outline, this book is cartoonish and childish, it reminded me a lot of the Marvel comics I read when I was a kid in the sixties.
But it's childishness is also its greatest strength, since Hodgson is the only author I know who can so potently conjure up the childhood terror of the dark.
Some of the visible monsters and hazards that are described are almost laughably preposterous, but Hodgson never blinks and ended up convincing me to suspend my disbelief.
One significant drawback is the meglomaniacal importance placed on the hero and his quest, it just doesn't quite ring true. A modern anology would be the Apollo 13 moon mission, I suppose, when millions of people were all thinking and worrying and hoping for the safe return of a handful of astronauts. So the phenomenon is not unprecedented, I just found that Hodgson treated it in an overly grandiose, facile and unconvincing way.
I read the same edition as one of the other reviewers below, the Ballantine one, and the second volume was somewhat edited, according to the preface. A lot of the excess romantic stuff was deleted. Even so, there are many long passages that are well nigh unreadable, because they are so over-the-top cutesy and mushy.
The faux 17th century writing style gets very wearing, as well, but it does succeed in significantly adding to the larger than life grandeur of the tale. It's a pity that Hodgson was killed in WWI, if he had lived to edit it, and clean up the style to make it more convincingly 17th century, the book would have benefited tremendously.
And another of the endearing qualities of the story is that the landscape and basic story premise is very psychologically evocative of any person living a hopeless, dispirited existence. It really succeeds as a psychological allegory, in my opinion.
Speaking of psychological things, Hodgson succeeds in describing many human emotions in a very tangible and palpable way. His
description of telepathic "good vibrations" pre-dates the hippies by many decades. And he is also very good as evoking how one's emotional state can drastically alter one's life in a very marked, and even physical, way. He was a writer of rare insight and sensitivity, and the world suffered a great loss when he died so young and needlessly.
It's been said in other places on the web, maybe not in these reviews here, that one of the most remarkable things about this book is that the tension is sustained for so long a time. I have to agree. One way that Hodgson does this is to adopt an almost journal-like structure for the story, each meal time in every day is covered, all along the quest. This keeps the focus of the story narrow and close down on the hero's level, so you never stop empathizing heavily with him.
All in all, I would say, that if you are a fan of fantasy, then you should definitely give this a try, it's an amazingly original and engrossing fantasy.