Yes, that would be very interesting, such as the floor getting slowly covered in shadow fire or other forces that send players to the next room, maybe there could be an element where players are split up in individual rooms, where teamwork is void and personal skill is survival, also maybe if the last player alive reaches the reward point, he/she can revive fallen players/player, the option to choose to revive only one player would make it more difficult to decide, there would be a revive timer, if you cannot come to a decision, then all dead players stay dead until the next reward point, it would start at a tier 1 level and move on until it is insanely difficult, so even if you have shivermisters and blitzers, there could be floating platforms with puppies,howlitzers or polyps, spawn points that are unrelated to the waves, and just throw out enemies to get in the way, groups of enemies together that were never encountered before together, all kinds of special damage and status effects, hmmm, this could really grow in to something fun :D.