I know it is early, but I still already set up a Discord server for the project.
The server is sure to come in handy for gathering ideas for plot points and puzzles!
Did you know that you can export meshes directly from Google Maps and use them as scale reference in your 3D modelling process. This will save a ton of time as you can create an asset library from real world locations and buildings.
The game is a mystery adventure. You are investigating what happened during a span of time through a series of interrogations. All of these interrogations you experience as gameplay flashbacks during which you will play as the interrogated person.