The other two I haven't played but here's what I've gathered from watching gameplay:
Most recent mods are also realistic-looking, in case you're not a fan of the original cartoony game aesthetic. The base content is a bit lacking, but this is easily fixed with mods, as you can find almost any animal from cockroaches to whales to obscure extinct animals. Animal and guest AI are much more complex and engaging, but can also be a bit buggy, particularly with mods that affect gameplay. It's fully 3D allowing you to roam your zoo in 1st person view. However being sprite based and because of how the exhibit requirements work, it doesn't give you as much freedom compared to other games, and the animal behaviors are quite basic. With all expansions it has a pretty good roster of animals (including marine and extinct) and items and lots of challenging campaigns to play through. Zoo Tycoon (2001) is a sprite-based game with an isometric view, unlike the other options. Honestly it depends on what you want from them, but here are some highlights: Regarding the fantasy option, ZT1 includes unicorns, yeti, bigfoot and Loch Ness monster, and ZT2 has that covered with many mods from unicorns to dragons to chupacabra to pokemon. I will copy my answer from a similar thread if that's fine, I haven't played WLP but I can give you my opinion about Zoo Tycoon and Planet Zoo. But in the end i would say that it's worth it. My biggest problem is that I had some performance issues, and it's a bit pricey. The animations are sublime, and it feels like you are watching a real animal. The game has some unfamiliar animals that the other games don't have, like the titan beetle. It allows for a lot of creativity, the level of detail is amazing, and the game has an overall cheery feel it shares with planet Coaster. After some googling the fantasy dlc seems to have the most. It's also not clear wich dlc has everything from the other dlcs. I have all of them, and every dlc is a seperate game in your steam library. My biggest problem with wildlife park 2 is the dlc. Wildlife park 2 has a lot of cool attractions and animals, like basilosaurus, and dragons. You have to make a pit and fill that with wate, and then surround it with a fence. The guests seems to be addicted to plant life, even in a rainforest. This adds a lot of creative freedom, but also makes it difficult to make symetric fences and paths. That being said, the game has some issues.
The ability to grow your own food was a big plus for me. Zoo tycoon 2 also has a fantastic modding community with mods like Walking with Dinosaurs, Radical Remake, and Jurassic world. The minigames are fun, and sometimes challenging. The guest mode lets you walk around and perform some duties.
Zoo tycoon 2 Ultimate collection fixes a lot of these problems, adds new attractions, and is in my opinion the superior game. This goes for the Dinosaurs too, but the marine animals are a bit easier to appease. The first zoo tycoon game has 2 fantastic dlc's, but it gets repetitive after a while, since animals are picky as hell, and if you ignore them the guests will call animal protection, temporary disableing animal adoption. Zoo tycoon 1 & 2: these 2 have stolen so much of my time, but not a second was wasted. I played all 3 of these games, and this is what i think of them: Useful Zoo Tycoon Links Links/Downloads/Discord Thread