The Fallout franchise started out as a turn based RPG with a top down perspective. Two major game releases were made in this format with a mysterious third game that was in development but never saw the light of day.
The Fallout IP was bought by Bethesda Softworks and after the success of Elder Scrolls: Oblivion, they released Fallout 3. The format had changed to a 1st/3rd person open world RPG with real time gameplay. The turn based system was replaced with a system of slowing down time known as VATs.
The franchise had several successful releases until the launch of Fallout 76 which was a technical disaster and was met with harsh critical response from gamers and critics. While attempts were made to improve the game, Fallout 76 failed to gain any respect from gamers and fans of the franchise.