Copied from Facebook group: ZT Biome
Jack Kerry
There's a very easy way to get a copy of Zoo Tycoon 1!
The game is in a category of games known as 'abandonware'
https://en.wikipedia.org/wiki/Abandonware
As abandonware, there is no longer any copyright enforcement on it whatsoever, and though it technically remains an 'ophan work' IP wise (and so still technically has protections under international IP law), it won't be enforced or recognised by anyone. Such works are legally preserved by museums and such all the time with no consequences.
There's a website called MyAbandonWare which acts as one such 'museum' of abandonware games, and allows people to download them for free. If a game still has a legal way to purchase and play it, it will have a link to that instead of a download button, so anything you can download there is totally safe to do so with a clean conscience.
Here's the link to Zoo Tycoon Complete collection: https://www.myabandonware.com/.../zoo-tycoon-complete...
They also have Zoo Tycoon 2 on there if you still wanna try that! Although it's only the base game, as the Ultimate collection is not yet abandonware, as it is still available to buy on amazon (as evidenced in your post)