Tom Clancy's Rainbow Six Siege is an upcoming first-person shooter video game under development by Ubisoft Montreal and to be published by Ubisoft. It was announced by Ubisoft on June 9, 2014 at E3. The game uses Ubisoft's AnvilNext game engine, and is the first game in the Rainbow Six franchise since Rogue Spear not to use Epic's Unreal Engine. Siege is considered to be a successor to Tom Clancy's Rainbow 6: Patriots, which has been cancelled. Like other titles in the series, it will focus heavily on teamplay and realism. However, there are major differences to older versions of the game, featuring a heavy multiplayer focus and destructible environments, similar to that of Battlefield franchise. A trailer at E3 2014 demonstrated a hostage rescue scenario and the game has initially received positive reactions. On March 12, 2015, Ubisoft announced that a closed alpha is in development, scheduled to be released exclusively for Microsoft Windows. A closed beta of the game was also announc...