As you might guess by the name, it's something of a gonzo style product. The zoo in question is literally a modern day sort of zoo, complete with many modern items, albeit a trashy zoo meant for tourists and that has apparently broken down, Westworld or Jurassic Park style. So it's perhaps not suited for your usual D&D game, even though it's statted for it (no specific system, but the armor class starts at 9). Seems almost like it's best suited for something like Mutant Future or possibly Starships & Spacemen 2e, though the tech level is modern, not futurisitc.
Similarly, the new monsters (22 of them) are mostly chimerical sorts of mutant animals. For instance, the Hazbroca seems to be part cobra, part orca or at least dolphin. The floppelope is part walrus, part giraffe, and part peacock. The muggerbeak is part gorrila, part turkey. The quincy raptor is part lynx, part kangaroo. Not all, though. Some are alien creatures, though most seemingly have some similarity to an Earth animal. Besides the usual stats you also get what they smell and sound like, as well as their hobbies and turn-offs.
