The studio's first title is At the Gates, a 4X strategy game similar to Civilization in which players command a barbarian kingdom with the goal of defeating both rival tribes and the waning Roman Empire.

Early in Civilization IV's development he wrote an extensive guide explaining how to utilize its Python scripting language,[5] and this led to him joining Firaxis for a programming internship in February 2005.

[6] Following the completion of Beyond the Sword, Shafer was named the lead designer and principal gameplay programmer for Civilization V, the next full title in the series.

While in this role, Shafer drew from his past modding experience and from computer games he had played as a child, most notably Panzer General.

In June 2017, Shafer joined Paradox Development Studio as a game director on an unannounced project, only to part ways in November of the same year, citing creative differences.