There is an amazon review of this book (which I think will be appropriately hidden behind a blue link that says: "read more reviews here") that claims that Cortazar is merely a magician or trickster whose writing lacks substance. It seems as if that reviewer specifically felt that 62: A Model Kit was little more than a collection of literary gimmicks.
This book is funny and entertaining, and yet, it is one of the most deeply serious books that I have read. Or I should say: it is the product of a serious mind that has faced unsolvable problems with vigor, and that (as in the mind) has come to appreciate those insurmountable problems as a gladiator might respect another skilled gladiator.
To illustrate I will speak of a common theme that runs through C.'s works:
the essential loneliness of being a human, caused by the incommunicable nature of inner experience (the inability to objectify terms like 'pain', 'thought', or 'mystical experience', the irrefutability of solipsism, problems posed by deception, etc.). Admittedly, Philosophical problems lead to very few (practical) places, yet they are impossible for some to leave aside. For those unfortunate, philosophically-challenged people there remains: experimental fiction that does its very best to remind you that the faces attached to the bodies which are walking around you on the street are not as inhuman as they look. Cortazar often seems to be telling his reader: "I too am overwhelmed by life as it is, by the feeling of being alone in public spaces, by societal pressures, and by the deceptions that separate me from my friends." It is a book made for the self-exiled and the isolated. It is also a novel that continually challenges the reader to look at the world without preconceptions, without ready-made (and possibly specious/vague) definitions.
The philosopher Wittgenstein once said that he had planned to make a philosophical work which consisted entirely of jokes, but that he had failed to write this book, since he lacked a sense of humour.
George Orwell also spoke of the need for intellectuals to constantly restate the obvious. I believe that humour is the most effective way to do this.
Humour is often effective when facing the feeling of being unable to say something... being unable to get others to understand things in the way that you do, despite clear language, mutual intelligence (or at least equal intelligence), and so on.
Laughter is often the pleasant expression of the (often somewhat exclusive) understanding between two (or three) people.
Cortazar is more than a trickster, possibly even more than a conjurer.
And 62: A Model Kit is his greatest achievement.