You walk through different corridors, avoiding dangerous and big monsters, to go against the weakers, until they stop appearing directly, enter empty, dirty, dangerous, and safe corridors with traps for surprises, working together you manage to go through safe paths.
In the end they arrive at a place that gives a choice to go out, since there is lighting at the end of all the corridors.
first hallway, a short one that is flooded without knowing the depth
second hallway, a wet path, with leaks and gases
third hallway, a long road with sharp obstacles, which are seen with blood
fourth hallway, one full of suspicious dusty furniture
fifth hallway, one that only sees the backlight, and its sides are totally dark.