Crowds of blood-thirsty monsters, crawling from every corner of the secret research base. Gloomy basements and modern labs, darkness changing into blazing bulbs. The only usual thing is: you're in a bad place alone, and there's no one to help you!
Most popular community and official game content for the past week.  (?)
What does popular mean?
It means the content you're seeing has been rated up more than it has been rated down for the given time period.