"Enig*ma (noun) : something hard to understand or explain." I have only perused Lord of Light once, and I believe a proper critique would necessitate a reread. That being stated, here it goes.
First, the positive aspects. I relished being thrust into the midst of Zelazny's unfathomable world without even a hint of guidance. He compels the reader to exert some effort and make sense of the surroundings. Are these individuals Hindu deities? Who is this talking monkey? The example that often comes to my mind is the initial 100 pages of Steve Erikson's Gardens of the Moon - what on earth was happening? In this kind of narrative design, the author makes a vow to the reader that either through tantalizing informational tidbits (if the author is skillful) or a deluge of explanations in a single scene (if the author is less adept), the mysteries will be elucidated - that is the payoff. I don't wish to transform this into a spoiler-laden review, but suffice it to say, Zelazny provides the nuggets.
I also adored the concept. I have never encountered anything quite like it. Strangeness, as Dan Simmons elucidates, is a prerequisite for a great novel. Lord of Light abounds in strangeness. According to Zelazny, "Lord of Light was deliberately crafted in such a way that it could be regarded as either a science fiction or a fantasy novel. On one hand, I endeavored to offer some justifications for the bizarre occurrences; on the other hand, I employed a style I associate with fantasy in the narration of the story. I wrote it thus intentionally, leaving some deliberate ambiguity, as I desired it to reside somewhat between both camps and not wholly within either. I did this because I noticed that there wasn't much material being written at that time that fit that description; because I wanted to see if I could accomplish it; and because I was curious about how such a book would be received."
What might have irked me is that it is indeed arduous to appreciate the subtleties of the characters' interactions, their motives, and whatever Zelazny is attempting to convey about religion, politics, or technology while one is striving to figure out what is transpiring! That is why, despite my enjoyment of this enigma on one level, I was left with a 3.5 rating. A second reading would undoubtedly enhance that score, potentially quite significantly.