I did something like this in the past but I can't be bothered to look for it or put "v2" in the title. So...
Idea #Uno:
I had this idea in the past in that one topic, an FPS in a Virtual Reality chamber.(In the game, not in real life) You could change a lot of things, and whenever you died it would malfunction and change everything. For example you could be shooting cowboys in Asia with laser weapons, then you die and suddenly you're fighting Russians on the moon with a portable cannon.
Idea #2:
I thought of this one recently since I've been playing a lot of racing games. A racing game with racing cars like F1, WTCC, NASCAR, and all that stuff, that plays out like a racing sim, but with a big twist. Mario-kart like items. Yeah. Things like Rockets, Boost, Repair, and well things like that. The cars will still have damage that affects the car. Normal racing rules apply.(other than the fact your shooting each other with various items) And you'll still have gas and tire wear to worry about. You'll be able to race on the real-world tracks like Monaco, Nürburgring Nordschleife, Daytona Speedway, etc. Or, create a track with a built-in track editor. You can also customize the cars. Up to 100 cars (!) can race at once, depending on the track that is.
So, tell your dream game that you would make.
edit: fiskd a gremar eror