Compromised Simulation is an anti-cheat system in the game. By changing device time by a lot and going back into the game, there's a high chance that you will see a red question mark saying "The space-time continuum has been broken.".
This can happen when you change the system time back by a large amount. The calculation of the time spent offline gets funky, due to the system time practically going backward, and so the game treats you as a potential cheater.
If you continue to change device time while there is a red question mark at the top of the screen, it means you are risking the stability of the game. This may cause intentional lag, lead to a black screen, or decrease FPS (frames per second). Your data will not be deleted, however.1
Note: While breaking the space time continuum over and over again, a user claimed to have noticed that the little question mark had turned black, but nothing else changed. They wondered what would happen if they keep doing it more. However, no photo evidence has been provided.
1 Requires confirmation.

