I'll have to let lemonyscapegoat describe it in full, but the game would have been a walking simulator.
An initial sketch of the character implied a movement mechanic which led an eviroment design and challenge, which eventually led to a villain who hampers your agency (the blasts from the radio tower) and an act structure. Most of this thematic heavy lifting was in a brainstorm discord call with lemonyscapegoat leading the way.