Mike Patton plays the aggression core; see his page for what else he's done.
Also, her Anger Core is literally The Darkness. That explains a lot.
Portal 2's "Adventure Core" is appropriately voiced by Nathan Drake, also known as Nolan North.
Throw It In: In this interview, Word Of God reveals that the blood splatters weren't meant to be in the game at all. However, they weren't even noticed until too late in development, and were so ingrained into the engine that, by that point, it would have been better to just leave them in the game. Valve went out of their way to remove the blood splatters for the sequel, however, hence its lower rating compared to the original.
In earlier concepts for a sequel to Portal, Cave Johnson was positioned to play a significantly larger role, including being subject to Brain Uploading (which, in the final release, he wanted, but he likely died before it could happen), and undergoing an existential crisis concerning the fact.
According to the Final Hours of Portal 2, Peer Review was going to contain a single player campaign as well. The original plan was for players to be either ATLAS or P-Body, who would be recruited by Rick to stop a brain-uploaded Cave Johnson from taking over the enrichment center. VALVe decided it would require too many resources for ''just'' a DLC...
