In some levels in the Instincts story, you can find a magazine named 
"Gamer Lamer". The magazine's cover has a mock-up picture of Gordan 
Freeman from Half-Life. The cover of the magazine reads 'Quarter-Life 
2 Amazing New Screenshots! Medal Of Shame, and Broom 3'. 
These are mockups of popular games, which are Half-Life, Medal Of Honor, 
and Doom 3.