A concept game, which has a name but I forget now what it is. It could be single or multiplayer, but all interconnected in some way. A game that a person can choose to play a very small part or a very large part. A game that has everything in it. The example I like to use is to imagine a single game that has all of the Sim games inside of it. SimCity, SimTown, SimEarth, Sims, Streets of SimCity, SimCopter, SimFarm, SimAnt, etc.
There is a more into this direction with the underlying aspect of No Man's Sky, which let you move from a spaceflight/combat game, though an atmosphere and down onto a planet. But the idea of the all encompassing game would be, say someone is playing on the SimCity mode and there is a tornado, it would effect people playing in the Sims or SimCopter mode. One big issue with a game of this design is that things could then occur that a player would have no ability to deal with, such as if a meteor would hit, then the person who was in SimTown or SimAnt or SimFarm mode would have a game over.
Aside from that, another game concept would be a reality simulator. Not really needing to be a simulator, but it is just an annoyance I have with games that have doors that cannot be opened, windows that cannot be broken, cars that cannot be driven, buttons that cannot be pushed, computers that cannot be used, etc. I want to be able to do everything and pick up/throw anything. Too much of a game is just there for show.
