Many elements from Civilization IV and its expansion packs have been removed or changed, such as religion and espionage (although these were reintroduced in its subsequent expansions). The game is based on an entirely new game engine with hexagonal tiles instead of the square tiles of earlier games in the series. In Civilization V, the player leads a civilization from prehistoric times into the future on a procedurally generated map, attempting to achieve one of a number of different victory conditions through research, exploration, diplomacy, expansion, economic development, government and military conquest. The game was released on Microsoft Windows in September 2010, on OS X on November 23, 2010, and on Linux on June 10, 2014. Sid Meier's Civilization V is a 4X video game in the Civilization series developed by Firaxis Games.