Some information may be incorrect, Ill fix any missing information pointed out.
Zoo Tycoon is more or less like your average Tycoon-brand management game, only this time your running, Big suprise, a Zoo.
The series itself is what you would call a "Spiritual Sucessor" to Rollercoaster Tycoon, which already has a thread here thanks to Shotacon.
Basic Gameplay (shamelessly stolen from Wikipedia article on ZT1 because im lazy):
The game was good, only there was some glitches. Thankfully with mod support these glitches were fixed plus people can add to the game by downloading or making mods for the game.
there were also 2 expansion packs for the game:
Dinosaur Digs: Adds: What else? Dinosaurs, plus some Phreistoric-themed buildings and scenery. a total of 20 new animals are added in this expansion pack plus Electrified Fences of diffrent types to keep them in their place, and phreistoric foliage.
Marine Mania: Adds: Water tanks for fish, dolphins, sharks, and other sea-mammals. You can also host Aquatic shows to please the crowds. even better, you can merge the water tanks with existing land exhibits to make more suitable habitats for animals.
Complete Collection: Adds all the aformentioned expansions and can work standalone.
Zoo Tycoon 2
This is the 2004 sequel, only with 3D environments instead of the basic 2D Isometric view.
Gameplay (Yet again stolen from wikipedia):
Theres nothing really diffrent to take note about in here, since it mostly stays true to the original game's routes, only with 20% Less animals and its in 3D instead of the Isometric 2D you remember. For the best expirence, buy the Ultimate Collection edition to get the base game plus all Expansion Packs.
List of expansions:
Endangered Species: Adds more Endangered Species into the game as the title says, plus adds more environmental-based missions for you to do, and Environmentally themed buildings. Example animals added into the game are the Orangtaun, Komodo Dragon, and even variant skins of current animals such as White Bengal Tigers and King Cheetah's, one of the bigger hallmarks of this expansion are Jeep rides and Sky Tram rides for transportation.
African Adventure: This adds African-based buildings and more animals into the game, including the Secretary Bird and, of course, Meerkats, also live lizard food. also fixes up the Jeep transportation so you can actually drive cars through exhibits so people get a closer look.
Dino Danger Pack: This was going to be a piece of premium content but was taken offline on the Zoo Tycoon Website, though you can still get it standalone or with Ultimate Collection. It basicly adds a small amount of dinosaurs. Yep, thats pretty much it.
Zookeeper Collection: more like a standalone pack, with all the aformentioned Expansions (except Dino Danger) along with the base game.
Marine Mania: Named after the same expansion pack in Zoo Tycoon 1, it adds 20 aquatic animals and basicly is a "Port" of the ZT1 Marine Mania pack, with all the bells and whistles of the classic expansion in Zoo Tycoon 2. you can still do aquatic shows and stuff.
Extinct Animals: Last expansion, it is kind of a port of Dinosaur Digs, only with more stuff to do, including Breeding DNA in the research lab to create animals. More stuff included is not just dinosaurs but even some extinct animals from the period (Wooly Mammoths, Giant Sloths, Sabre-toothed Tigers etc.)
Ultimate Collection: works the same as Zoo Tycoon 1's Complete Collection pack, adds all the ZT2 Expansions in one large standalone pack.
Yes, you can also mod the Sequel, but the entertaining part is the rather large amount of machinimas on Youtube made using ZT2, absolutely all of them are crap.
Finally, some Q&A:
Will there be a Zoo Tycoon 3?
Nope, not with Blue Fang Games having cut their deal with Microsoft in 2009, though it could happen.
Where can I get these games
Amazon.com, dunno about other dealers though.
When was this released?
The first one was released in 2001, while Zoo Tycoon 2 was released in 2004.
http://zootycoon.com/ Main website for ZT1 and 2.
http://www.freewebs.com/artifex-home/ Great mods for Zoo Tycoon 2.
http://www.amazon.com/Zoo-Tycoon-Com.../dp/B0000A2TPE Zoo Tycoon 1 complete collection buy page from Amazon.com.
http://www.amazon.com/Zoo-Tycoon-2-U.../dp/B001BZ2F56 How could I forget the buy page for Zoo Tycoon 2?
^Gameplay video for ZT2^
^Plus gameplay video for ZT1^
^Killer Penguin easter egg from Zoo Tycoon 2's Extinct Animals expansion.^
^Deminstration for mods in Zoo Tycoon 1, I still dont know how to download a mod for ZT2.
Ill try to update when I feel like it, enjoy.