Portal 2 is playable at GamesCom, and while some people are playing it, others are filming it being played, so everyone else can enjoy it!
In case you're wondering, no, that is not the voice of an over-eager booth assistant. It's Wheatley, your AI companion in the game, who is voiced by British radio man, actor and co-creator of The Office and Extras, Stephen Merchant.
He may sound annoying at first, but I'll take annoying if it means there's somebody to talk to in the game that's not a psychopathic AI bent on my destruction. Unless he turns out to also be a psychopathic AI bent on my destruction, in which case, screw you, Wheatley.