Bethesda Softworks has filed a lawsuit against Warner Bros. Interactive Entertainment and Behavior Interactive for copyright infringement, alleging the recently-released 'Westworld' iOS game copies gameplay elements from 'Fallout Shelter,' and potentially some of the game's code.

Filed in a Maryland U.S. District Court, the Bethesda lawsuit alleges 'Westworld' uses the "same or highly similar game design, art style, animations, features, and other gameplay elements" as the company's popular 'Fallout Shelter,' reports Polygon. Among the examples given are the underground base creation features and the "cartoonish 2D characters in a 3D environment" aesthetic that both games adopt.

'Fallout Shelter,' released in 2015, tasks players with building and managing an underground bunker, keeping the facility in operation by tending to the needs of its occupants, and by sending vault dwellers out to the rest of the world.

Released this week and based on the TV show of the same name, 'Westworld' is a "training simulator" where players must build underground maintenance and control facilities for the theme park. At the same time, they have to manage android "hosts" and the experiences of guests in the theme park, keeping everything running smoothly while fixing occasional host glitches out of public view.

Fallout Shelter

The lawsuit goes further in its claims, alleging that 'Westworld' reuses code used in 'Fallout Shelter.' According to the suit, Behavior was contracted to work on 'Fallout Shelter' in 2014, building the game based on Bethesda's design and direction, with all materials created for the game owned by Bethesda.

"Behavior breached its contract with Bethesda and utilized its restricted access to Bethesda's intellectual property, including Bethesda's copyrighted code, trade secrets, and other rights," it is claimed, which allowed Behavior to "compress its development time, reduce costs," and provide the same "widely popular gameplay experience found in 'Fallout Shelter'" to players.

Westworld

As proof of Behavior copying the code and effectively reskinning it, the filing advises a big found in an early version of 'Fallout Shelter' has also been found in 'Westworld,' suggesting the same code base was used for both games.