Bethesda is suing Warner Bros Entertainment and Canadian developer Behaviour Interactive over claims the latter two companies stole its IP and trade secrets to make “blatant rip-off” mobile game Westworld.

The title is based off the hit HBO TV series of the same name and tasks players with building and managing a theme park. Below that, they must construct rooms to maintain operations.

The game’s developer Behaviour Interactive previously worked on Fallout Shelter. That title has been downloaded more than 120 million times and recently landed on Nintendo Switch.

Legal fallout

Law360 reports that Bethesda alleges Behaviour has breached its contract with the publisher and used copyrighted code, trade secrets and other rights.

This, it claims, helped it “compress its development timeline, reduce costs and quickly bring the Westworld mobile game to market”.

The lawsuit also claims Westworld has “highly similar” game design, art style, animations and features to Fallout Shelter.

One of the key allegations states that the Behaviour used “the same copyrighted computer code created for Fallout Shelter in Westworld”, with a similar bug appearing to that of one in an early release of Fallout Shelter.