OpenTTD is a clone of the Microprose game "Transport Tycoon Deluxe," a popular
game originally written by Chris Sawyer.  Significant enhancements from the
original game include bigger maps, new AI, stable multiplayer mode, dedicated
server mode, and many in-game updates.

Historically, users of OpenTTD needed access to several original Windows data
files in order to successfully run the game.  However, now there are two
options:

1.  Using open source data files.

There are now open source equivalent files for the graphics (opengfx), sound
(opensfx), and music (openmsx) data files.  This script includes support for
these three extra downloads and will move the files into the right place so
long as OPENDATA=YES (which is the default).

2.  Using the original Windows data files.

Alternatively, the user can still use the original Windows data files.  If the
original Windows data files are going to be used, then they must be copied into
the /usr/share/games/openttd/data directory before the game can be played.
List of the required files: sample.cat trg1r.grf trgcr.grf trghr.grf trgir.grf
trgtr.grf.  Note that the user can either set OPENDATA=NO in which case the
open source data files will not be used by the script and OpenTTD.  Or, the
user can keep OPENDATA=YES in which case the open source data files will be
included giving the user the ability to choose which data file set (original
Windows or open source data files) to use within the game options menu.

See the readme.txt or http://wiki.openttd.org for more information.