Tombstone City: 21st Century is a single-player video game designed in 1981 exclusively for the Texas Instruments TI-99/4A home computer.

The player controls a schooner, shooting aliens (called Morgs) and tumbleweeds in order to woo people back to live in an abandoned city somewhere in the Southwestern United States. The score is labeled as “Population”. The game ends when all schooners are gone.

(c) http://en.wikipedia.org/wiki/Tombstone_City:_21st_Century