OpenRCT2

A legitimate copy of the game is required to play, either bought from

Steam
GOG.com
a retail CD version

Instructions on how to extract game assets and setting up the game can be found on the official OpenRCT2 website (innoextract is needed for extraction).

OpenRCT2 is an open-source re-implementation of RollerCoaster Tycoon 2 (RCT2), expanding the game with new features, fixing bugs and raising game limits.

NOTE: OpenRCT2 also supports RollerCoaster Tycoon 1 game files.

pacman -S openrct2 innoextract

For the development version install the AUR package:

yay -S openrct2-git

The game will look for an installation of either RollerCoaster Tycoon 2, Deluxe (RCT1) or "Classic" installed via Steam for game files.

If you have the GOG version, OpenRCT2 will offer to extract the files from the downloaded EXE file and set things up for you.