The rules to beating the game were, in fact, very simple, as they, the ten thousand players, needed to beat all nine demons in order to finish the game. The same ten thousand players were all struggling with their levels, as there was no traditional way to level up. The easiest ways to level up would take them in a different direction, then they would need to be to face not just one... not just two... or three... but nine different demons. Maxed out in everything, demons that they somehow had to take down to finish this game.
However, there was something that was on their side, as the ten thousand players could respawn endlessly, as long as there was at least one of them present within the game, their side would not lose. The countdown to when they could respawn was extremely small. Thus, by the time they take out that one last player, another would respawn, then another, and another, and it would snowball. That was their biggest advantage, and they could spam it to no end, as there was nothing that was stopping it from happening. As they die, then come back, die, then come back, as they were basically immortal in that sense. To the point where death could claim them, however, it could not keep them, as they would quickly be reclaimed by life after an extremely short period of time. This immortality that the player had did not just extend to The Decagon game world either. Now that it was revealed that what they thought, up until this point, was reality, was really just another level of the game. Their immortality extends there as well. Here was just that nothing could harm them, as they could still feel the pain, but that would be all. The result of death was fully removed from the equation. They would pass out from the pain and exist like that until someone removed them from whatever scenario they were in.
This was a mystery to the players as to why they were at least physically invulnerable outside the game world of The Decagon, to the reality portion of it. They were not taking any physical damage; regardless of what, they were still feeling the results. Getting stabbed would still result in the feeling of being stabbed, and breaking something would still result in feeling the pain of it being broken. This physical invulnerability was probably put into place by the developers to ensure that the players could not just decide to all take their own lives at once, thus beating the game that way. Though that would be a choice that they should be allowed to make, to finish the game, it was explicitly stated that this means of attempting to beat the game. The players' conditions to beat the game were to find and kill the nine players that were now the nine demons of The Decagon. The nine demons were nine randomly chosen players who were maxed out within the game; their status, skills, level, etc., were only for the game portion. They did not exist outside the game world of The Decagon, revealed to be two layered game(one consisting of the game world and a recreation of reality). It was thus considered unfair to the nine players who were the demons if they could be taken out by merely discovering which player they were.
Why it was considered unfair was something the players would not know, as that information was not something they knew. The developers never contact them after they made the reveal and stopped being contactable afterwards as well. They could not get in touch with them at all, that is to say, if they were ever able to in the first place, as what they thought was reality was merely a different aspect of the true The Decagon game world, after all. Thus, the issue of who to trust had come up amongst the players, as there was a one in ten thousand and nine chance that any one of them was one of the nine demons. Demons that were not aware of who was one of their fellow demons, just that there were eight other ones of them out there now, and that was it.
While the players were immortal in both layers of the game, to different degrees, there were those players that decided to, rather then break the rules, attempt to discover loopholes that would allow them to take out all every other player and then themselves, rather then ever attempt fighting something that was basically akin to end game superboss with starting level everything in world where leveling up was fully player dependent. Thus, they became player killers, as even in a game and scenario such as this, people like that had appeared still within The Decagon, as of course they would. Though that was something those at Kynatech had anticipated and planned for, as they were going to allow them to ruin the game they had developed. Though they were not going to deny their choice to attempt to do so, they did make sure that they would pay the price for doing so. However, there was a catch, as there was one area where there was no grey zone about things, as intent was not a factor at all. If the line was crossed, then the line was crossed, and that was all there was to it. There was no if, and, or buts about it, as once it was done, it was done. There were no take backs, do over, or even a mulligan afterwards.
Killing a player, regardless of which layer of The Decagon they did it in, results in a ban. A ban not from the game itself, but from any and all settlements, regardless of how big or small they were, for good. They were basically stuck existing outside, both within the game world and the reality portion of it as well. They were booted out of the facility and left to live in a tent on the edges of the facility grounds. The tent itself was still connected to their original room, but they could no longer access the facility itself. The door just led to the outside, where their tent was located. The outside of the facility was twice the size of itself. They were also randomly placed somewhere along the borders of it.