you’ll get better answers if you get more specific. Can you describe an example of a condition you want to watch?
actors in the level can report when something important has happened either directly to the game mode, or via interface. This way they can talk to the game mode but not tie the game mode to them.
So for instance, an enemy is killed, it sends interface message to game mode called “On Enemy Killed”. The game mode is keeping a counter and increment it by one. When the counter reaches 10, then you fire off, “Mission COmpelted” event.
So in this way, the game mode knows the rules of the game and actors in the level report about what is happening in the game. But actors are not tied to the game mode and game mode is not tied to any actors. They only reference the interface.