The game hasn't changed in fundementals, build a zoo, more expensive animals generate more visitors and money. There has been an astounding leap in graphics though. Each animal has to be built a personalised enclosure, with its correct biome and fencing...a wire fence wont keep in a tiger; as my visitors learned the hard way.
The detail of each specfic biome is impressive, tundra, temperate, rainforest; all have specfic trees; plants and even rock formations. The most notable change from 1 to 2, is the 'keeper mode'. This mode allows you to walk around the zoo and interact with visitors and animals like a keeper, feeding, bathing and sometimes healing them..the animals that is, not the visitors; that another game entirely.
A wide range of themed kiosks and amenities are available for purchase or to download. Safari like jeep rides and sky trams are also incorporated and can be ridden from the perspective of the visitor. I particularly enjoy taking the safari rides around large savanha enclosures.
Each of the expansion packs add a new type of animal, I most recommend the 'Africa' and 'Endangered Species' packs.
Be wary though, the larger the land you choose, and the more you build up your zoo, the slower the game becomes. You really do need quite an impressive computer to run this game with its expansions for any length of time.
Impressively detailed and by far the best of the 'Tycoon' series.