Step into Room 24, which is infested by humans as well as cockroaches. Which of the two that causes you more disgust depends a lot on your philosophy for life. But only one may survive. Team up and kill the humans as a cockroach, or put your can of bug spray to work and rid Room 24 of cockroaches as the humans. The best of the best can become the ghost.
Move with the mouse and left click to either use your bug spray, or eat attack the humans. If enough cockroaches can attack a single human, they become stunned and must be saved by other humans.
You can only see what's in front of you with a flashlight effect. Use that to your advantage
Earn a score of 20,000 and ascend to ghosthood, allowing you to turn the lights and on off, or shake the room (as a human.)
The density is reflected in the map. Red hotspots have a lot of enemies, while green hotspots signal allies.
Teamwork is key, no matter whether you're human or roach.
And keep scanning around you with the flashlight to catch anyone trying to sneak up on you.