This book, written by creature-effects designer Alec Gillis, has a number of laudable features. The foremost of these is the realistic portrayal of what interstellar travel and the technology that will allow us to accomplish such an endeavor will be like in the twenty-first century (the comparatively near future), if it comes that soon at all. The mission is very mass-constrained, with just one passenger, residing in cryogenic stasis for most of the long voyage: there is no "warp drive" or "hyperspace"; the journey is slow, dark, and tedious, a cruel reality reflected in the sparsely text-covered, expansive pages of the book, with their ebony paper evoking the dark loneliness of deep space. Another favorable attribute in the stunning photography, in particular the harrowing self-portraits. The plot is admirably engaging, too, keeping a fair distance from a sensationalistic Man vs. Wild-like mood while not detracting from the protagonist's dire straits towards the end of the yarn, nor becoming overbearingly harsh and more about a man's struggle for survival than the documentation of extraterrestrial life; this is sharp contrast to the relatively placid (some would say dull) plot of Wayne Barlowe's oft-compared Expedition.
But I've got a few bones to pick with Gillis. For one thing, he is not a zoologist, and it shows: he seldom explains the finer anatomical intricacies of the creatures he has created, their ontogenies, or much about their ecological importance; instead, me mostly concentrates on their appearance, which usually incites some kind of visceral (and often negative) emotion in a human, making plain his Hollywood background. In a similar vein, he is clearly oblivious to taxonomic nomenclature: Gillis capitalizes the species and genus names of his creations (for instance, Infestus Liberi), rather than only the latter, as is proper. Another oversight on his part is the decidedly Earth-like appearance of Proxima Centauri 4 (with its jungles, ice-caps, oceans, etc.) and its biota: the flora has chlorophyll, and thus the atmosphere is conveniently suitable for the marooned hero of the book, while the fauna and ecosystems are not as alien as Gillis could have made them, with much of the construction of both decidedly familiar to Earthlings. Infestus, for instance, are indicated on p. 113 to have "compound eyes." I personally find it highly doubtful that alien life forms would evolve eyes in the first place, much less ones so closely matching the structure of those belonging to our familiar arthropods. As a final criticism, the word "breaching" is replaced with "breeching" on p. 95. This is a bit more irritating (to me, at least) than it might sound.
In conclusion, I would say that Worlds will definitely satisfy most people looking for extraterrestrial thrills, as it reads much like a good science-fiction novel and less like a xenobiology textbook, while its stunning (and even artistic) pictures never disappoint (at least in my case). However, if you're a conjectural zoology geek, you would probably do better to purchase Expedition (which is near-flawless, in my opinion), with its detailed and somehow more realistic profiles of the organisms and ecosystems of Darwin IV.