Open-source re-implementation of RollerCoaster Tycoon 2

 OpenRCT2 is an open-source re-implementation of RollerCoaster Tycoon 2
 (RCT2). The gameplay revolves around building and maintaining an
 amusement park containing attractions, shops and facilities. The player
 must try to make a profit and maintain a good park reputation whilst
 keeping the guests happy. OpenRCT2 allows for both scenario and sandbox
 play. Scenarios require the player to complete a certain objective in a
 set time limit whilst sandbox allows the player to build a more flexible
 park with optionally no restrictions or finance.
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 RollerCoaster Tycoon 2 was originally written by Chris Sawyer in x86
 assembly and is the sequel to RollerCoaster Tycoon. The engine was based
 on Transport Tycoon, an older game which also has an equivalent
 open-source project, OpenTTD. OpenRCT2 attempts to provide everything
 from RCT2 as well as many improvements and additional features, some of
 these include support for modern platforms, an improved interface,
 improved guest and staff AI, more editing tools, increased limits, and
 cooperative multiplayer. It also re-introduces mechanics from RollerCoaster
 Tycoon that were not present in RollerCoaster Tycoon 2. Some of those
 include; mountain tool in-game, the "have fun" objective, launched coasters
 (not passing-through the station) and several buttons on the toolbar.