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.

Several original Windows data files 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

Again, several original files must be copied from the game cd or equivalent.
See the readme.txt or http://wiki.openttd.org for more information.