The player is responsible for building out the park such as modifying terrain, constructing footpaths, adding decorative elements, installing food/drink stalls and other facilities, and building rides and attractions. Many of the rides that can be built are roller coasters or variations on that, such as log flumes, water slides and go-kart tracks. The player can build these out with hills, drops, curves, and other 'special' track pieces (such as loops, corkscrews and helixes), limited only by cost and the geography of the park and other nearby attractions. There are also stationary rides, such as Ferris wheels, merry-go-rounds, and bumper cars, most of which only contain single ride 'piece' and are very limited in terms of variation. Rides are ranked on scales of excitement, intensity, and nausea, all which influence which park guests will ride those attractions and how they will behave afterward. The player can set the prices for park admission rides and guest amenities, although care must be taken so that guests will not think prices are too high. The player is also responsible for hiring park staff to maintain the rides, keep the park clean, enforce security, and entertain guests. Players may also invest in 'research', which unlocks new rides and improvements as time goes on, though it costs money to continue research. Research in a particular category is disabled when all attractions in that category are researched.