Before I begin, I understand the game is still in development and things are subject to change. Therefore, if my criticisms are outdated in the future, I will gladly remove this review.

First off, animal variety. This is probably my biggest criticism. Currently, of the 27 animals available, only 4 types of animals are non-dinosaurs. Frankly, I like dinosaurs, but to have around 85% of the animal cast be dinosaurs is too much. If the game was exclusively about park building for dinosaurs, 23 types at this time would be astounding. It helps that the dinosaurs come in a variety of forms. But, that variety caps out when you see too many of a similar type of dinosaur. I wish I could capture how my mild reaction was when I saw yet another type of Sauropod. I predict my answer to other situations like, “Another Theropod? Oh boy.”
Prehistoric Kingdom is planned to cover around 10 Cenozoic creatures and 40 Mesozoic dinosaurs. That's 80% dinosaur. I only recently discovered that the game was planned to host creatures from the PALEOZOIC - WHAT?! You’re telling me that all those interesting creatures were cut?! No Gorgonopsids? No Athropleura? No Dimetrodon? No trilobites? No Ichthyostega? That’s a whole era of Earth just ignored. Besides, there were other animals in the Mesozoic besides Dinosaurs. As well, there are more animals besides mammals in the Cenozoic! I hope we see some Paleozoic and non-dinosaur animals in mini-exhibits.

Second: Park Building. Simplified to one word: Frustrating. I tried constructing a park months ago, and the result was hideous. Grass clipping through the floor, objects floating despite my best efforts to flatten everything beforehand, ugly abysses where bathroom entrances should be. My park guests just walked all over the interior of my prefabs - on top of tables, on the counters. Optimistically, I returned today to see if any improvements were made. More frustration. My roads looked horrid. Terrain poked out at every seem. Flattening the terrain did nothing. Sometimes the grass would disappear as it should. Sometimes it flickered at me in defiance. I placed a mini-exhibit and despite everything I tried, I could not get the terrain OUT of the exhibit! The bottom is made of concrete, not uneven dirt and grass! I've never had this much of a headache from a park builder.

Third: Quality. Nigel Marven's narration is well done. It's a treat to hear him feed us tidbits about the animals we exhibit. However, hearing the same bits over and over does get annoying.
The genetic diversity of animals is interesting and gives every solitary animal the touch of uniqueness that you would expect of real animals.

Closing thoughts: I really want this game to be successful. The game still being in development gives me hope. But, the current state of the game leaves me wanting more. Best of luck to the dev team.