Would they make their presence and awareness of the game-situation known, or would they keep their simulated heads down and continue poking undetected, hoping that some automated bug-cleaner doesn't wipe them out?
Appears to be a historical simulation of some sort, centered around 2015-2016 C.E., perhaps better known as the present-day world. The game/simulation seems precise/detailed to the atomic (or perhaps subatomic level), and is an open-world, at least as far as Earth's surface is concerned. The game-aware group appear to be exclusively non-player-characters, or NPCs, (at least none have any memory of having been possessed!).
It took some effort to get here, but the group of similarly awaken NPCs are able to identify player-characters (PCs) by sight, as they now (did not have this ability before) can see a red aura or glow around the PCs. The group haven't exactly done a scientific survey, but the PCs seem to comprise about 0.5% of the population, with some presence in all social classes, but with a marked predisposition towards the ultra-rich and famous.
It's hard to be exactly sure, but the 'make-PCs glow red' achievement strongly suggests that the group's methods so far gave them access to some run-time debugger or perhaps a limited section of the source code. The PCs seem unaware of the situation.
It seems likely that the "source" civilization is probably a descendant of humanity, with generally higher technology levels than the present (just running this Earth sim would tax in-sim technology to the breaking point), and uncertain motives in running this game/simulation, but otherwise the PCs have not yet evidenced strongly superhuman cognitive or physical abilities.
Edit: To clarify, the PCs can be assumed to know that the NPCs are self-aware, since that's the point of the simulation. The PCs do not know that the NPCs have identified them as coming from "outside".