On page fourteen of the LAB RAT comic, on the table, next to the portal gun is a Zero-Point Energy Field Manipulator/Gravity Gun. On the wall there is a health charger and a HEV charger. This, the gravity gun, proves that Black Mesa have been stealing things from Aperture. And that makes Half-Life 2 Awakening completley useless, since Mossman tell Shephard that they have a prototype of their latest research, the Gravity Gun. Also, in the down-left corner, there is a combine health panel, which proves that the combine found the Borealis and used some of its technology.
Also, on page 9 you see Chell’s file. There is a lot of ones and zeroes, which can be transalated in to The Cake Is A Lie. Which makes three present Cake references in Portal 2: The above, the scrolling text on the monitors that can be transalated in to the cake recepie and of course, the GLaDOS Emergency Shutdown and Cake Dispensery door.