The geography and landscaping of the park can be modified, allowing the player to lower/raise terrain and add water to improve the park's attractiveness, as well as to allow rides to fit into their surroundings more easily.
There are 21 scenarios included with RollerCoaster Tycoon, as well as 30 more in the Corkscrew Follies expansion pack, and another 30 in the Loopy Landscapes expansion pack, totaling to 81 scenarios if the whole set is installed.